유튜브는 미국의 온라인 영상 공유 플랫폼으로 캘리포니아주 샌브루노에 본사를 두고 있다. 2005년 2월 페이팔 출신의 채드 헐리, 스티브 첸, 자베드 카림이 창업하였으며, 2006년 11월 구글이 16억 5000만 달러에 인수하였으며 현재까지 구글의 자회사로 남아 운영되고 있다.

유튜브는 유저들이 영상을 업로드해서 자유롭게 감상하는 서비스를 기반으로, 좋아요와 싫어요 버튼, 공유하기 기능, 플레이리스트 추가 기능, 리포트 기능, 영상 댓글 기능, 구독 기능을 갖추고 있다. 유튜브의 기반이 되는 바탕으로 '내 손으로 방송하자' (Broadcast Yourself)라는 수년간의 슬로건은 물론, 유저 프로필의 명칭을 '채널'로 설정함으로서, VOD의 영역을 대폭 확대시켜 누구나 텔레비전 방송처럼 개인 방송을 운영할 수 있도록 만들었다.

유튜브는 광범위한 유저 제작 영상과 기업 매체 영상을 제공하고 있다. 유튜브에서 볼 수 있는 콘텐츠로는 비디오 클립, TV 프로그램 클립, 뮤직 비디오, 단편 영화, 다큐멘터리 영화, 음성 녹음본, 영화 예고편, 라이브 스트리밍, 브이로그, 단편 오리지널 영상, 교육 영상 등이다.

2017년 2월 기준으로 유튜브에서 매 1분마다 업로드되는 동영상 콘텐츠의 양은 약 400시간 이상에 달하며, 하루 동안 유저들이 동영상을 보는 시간은 모두 합쳐서 10억 시간에 달한다. 2019년 5월 통계에서는 업로드되는 콘텐츠의 양이 1분당 약 500시간으로 집계되었다. 이와 함께 분기별 광고 수익 보고서에 따르면 유튜브가 벌어들이는 연간 수익은 150억 달러에 달하는 것으로 조사된다.

한편 유튜브는 운영 면에서 여러 가지 비판에 직면해 오기도 하였는데, 영상 업로드 과정에서 불거지는 저작권 문제 대처,

## 설립과 성장

### 유래
유튜브는 페이팔에서 직원으로 근무하던 채드 헐리, 스티브 첸, 자베드 카림이 설립하였다. 페이팔에 입사하기 전, 채드 헐리는 펜실베이니아 주립 인디애나 대학교에서 디자인을, 첸과 카림은 일리노이 대학교 어배너-섐페인에서 컴퓨터공학을 전공했다.

2005년 2월 14일 'YouTube.com'이란 도메인 주소가 열렸으며, 4월 23일에는 비디오 업로드 기능이 처음으로 활성화되었다. 당시 사이트 이름은 'Tune In, Hook Up'으로 세 사람이 스스로 생각한 아이디어였다. 초창기 사이트 컨셉은 온라인 데이팅 서비스였으며, 결과적으로 실패하였지만 비디오와 업로드 플랫폼은 예외로 남게 되었다.

### 영상 공유 서비스로의 전환
2004년 미국에서는 제38회 슈퍼볼 경기 하프타임 시간에 펼쳐진 저스틴 팀버레이크와 자넷 잭슨의 공연에서, 잭슨의 가슴 가리개를 뜯어내는 연출이 전국민이 보는 생방송에 노출되어버린 사고로 인한, 이른바 니플게이트 논란이 있었다. 하지만 정작 이 사건에 대한 영상을 인터넷 그 어디서도 찾을 수 없었던 세 사람은, 영상을 공유할 수 있는 온라인 플랫폼이 없다는 문제를 깨닫고, 최초의 대규모 비디오 공유 플랫폼이 되기 위한 웹사이트 개편에 나섰다.

이 시점에서 유튜브에 올라온 최초의 동영상으로 'Me at the zoo' (동물원에 간 나)라는 영상이 존재한다. 2005년 4월 23일에 업로드된 이 영상은 유튜브 공동설립자인 자베드 카림이 샌디에이고 동물원을 배경으로 시험 삼아 찍은 영상이며, 아직까지도 삭제되지 않고 남아서 1억 2000만 조회수와 좋아요 500만 개를 기록하고 있다.

사이트 개편 과정에서 헐리는 자신의 디자인 실력을 발휘해 유튜브의 로고를 만들고 레이아웃을 설계하는 등, 웹사이트의 외형을 고민하는 쪽을 맡았다. 2005년 6월에는 유튜브의 슬로건을 'Your Digital Video Repository' (당신의 디지털 영상 저장소)로 정했다.

### 운영과 성장
유튜브는 차고를 임시 사무실 삼아 시작하는, 일종의 엔젤 투자 기업으로 첫발을 내딛었다. 2005년 11월 벤처기업 시쿼이아 캐피털에서 유튜브에 350만 달러를 우선 투자하고,롤로프 보타 사 (시쿼이아의 파트너 기업이자 전 페이팔 CFO)도 유튜브 이사회에 합류하게 되었다. 2006년 4월, 시쿼이아와 아티스 캐피털 매니지먼트는 유튜브에 800만 달러를 추가로 투자하여, 유튜브는 서비스 개시 몇 달만에 엄청난 성장을 맛보게 되었다.

2005년 12월에는 대대적인 첫 기능 업데이트가 실시되었다. 댓글을 단 사람의 영상 업로드수, 좋아요수, 친구수가 댓글란에 직접 표시되도록 하였으며, 영상의 외부 링크, 추천 영상의 댓글수, 영상 리스트 검색 결과와 채널 페이지의 순위표를 새로 추가하였다. 이와 함께 "Broadcast yourself. Watch and Share your videos worldwide!" 라는 새로운 슬로건도 선보였는데, 이는 나중에 "Broadcast yourself"로 짤막하게 바뀌었다.

2005년 5월 베타서비스를 개시할 당시 유튜브는 한달에 약 3만 명의 트래픽을 기록하였으나, 출범 6개월을 맞이한 시점에서는 하루에 200만 명 이상이 방문하는 웹사이트로 발돋움하였다. 2006년 3월에는 유튜브에 올려진 영상 개수가 총 2500만 건을 넘었으며, 하루에 2만 개의 업로드가 이뤄지는 수준으로 성장하였다. 6월에 미국의 방송사 NBC와 마케팅, 광고 파트너십을 체결하게 된 유튜브는 

하지만 이런 성장 속에는 어려움도 있었다. 급격한 성장으로 불어난 유저수는 곧 유튜브가 그에 걸맞는 기술적인 소통을 통해 계속해서 유지해야 한다는 뜻이기도 했다. 유튜브 측은 서버 장비와 브로드밴드 인터넷 접속량을 계속해서 도입해 나가며 유입을 뒷받침했다. 점차 증가하는 저작권 위반 문제와 광고화 수단 부족 문제 역시, 유튜브로 하여금 훗날 자체 비디오 서비스를 운영하다 실패를 맛본 구글 측에 위탁하는 원인으로 작용하게 되었다. 

2006년 한 해 유튜브는 알렉사 통계에서 5번째로 가장 많이 찾는 웹사이트로 조사되었으며, 성장률로 따지면 마이스페이스를 한참 능가하고 있었다.

## 구글의 인수
2006년 2월 유튜브 최초의 광고가 게시되었다. 유튜브 자체 권한으로 게시되는 참여형 영상 광고의 형태로서, 광고를 클릭하면 독점 콘텐츠를 볼 수 있는 기회를 제공하는 방식이었다. 

참여형 영상 광고는 지금처럼 플랫폼 전체에 한번 광고하는 것이 아니라, 특정 채널에서 특정 프로모션을 링크하도록 만들어진 것이었다. 이 같은 광고 방식을 도입한 뒤 2006년 8월 유튜브의 CEO 채드 헐리는 "우리는 사람들이 콘텐츠를 감상하기 전에 광고를 보도록 강요하는 것보다 더 나은 방법으로 브랜드에 관여할 수 있다고 생각한다. 인터넷 상의 아무에게나 그런 경험에 만족하냐고 물어보라. 아마 그렇지 않다고 대답할 것이다"라는 말을 남겼다. 당시로선 광고 영역을 확대하여 모든 유저에게 광고를 노출하는 것이 유저 친화적이지 못하다고 여겼던 셈이다.

2006년 10월 9일, 미국의 검색 엔진 기업 구글이 16억 5000달러 규모의 주식을 매입하여 유튜브를 인수할 것이라는 소식이 발표되었다. 11월 13일에는 주식 교환이 완료되어 완전한 구글의 자회사가 되었다. 당시까지 기록한 구글의 역대 인수 건 중에서 두번째로 가장 큰 규모였다.

2006년 말 미국의 〈타임〉지는 올해의 인물로 '당신' (You)을 선정하고, 거울이 덧씌워진 유튜브 화면을 표지로 실었다. 올해의 인물 선정과 함께 타임지는 유튜브를 비롯한 UCC 미디어를 다루고, 유튜브의 창업자와 함께 컨텐츠 크리에이터도 몇 명 소개하는 특집 기사를 냈다. 월스트리트 저널과 뉴욕 타임스 역시 유튜브에 게시되는 콘텐츠를 리뷰하고, 사내 소통과 사원모집에 끼친 영향을 특히 높이 평가했다. 〈PC 월드 매거진〉 역시 유튜브를 2006년 최고의 상품 10위 중 9위로 선정하였다.

2007년 2월 7일에는 구글 측의 미 증권거래위 (SEC) 인수 신고로 유튜브 투자자들의 수익내역이 공개되었다. 2010년 창업자 채드 헐리의 수익이 3억 9500만 달러, 스티븐 첸의 수익이 3억 2600만 달러로 드러났다.

## 지속적인 성장
It is estimated that in 2007, YouTube consumed as much bandwidth as the entire Internet in 2000.

YouTube's early website layout featured a pane of currently watched videos, as well as video listings with detailed information such as full (2006) and later expandable (2007) descriptions, as well as profile pictures (2006), ratings, comment counts, and tags.

In March 2007, YouTube launched the YouTube Awards, an annual competition in which users voted on the best user-generated videos of the year. The awards were presented twice, in 2007 and 2008. Video contests with prizes existed as early as December 2005, possibly earlier.

At "youtube.com/browse", there were various web feeds, including a list of the videos most recently uploaded to the site, suggesting an upload rate of approximately two videos per minute as of April 2007.

In June 2007, YouTube launched a mobile web front end, where videos are served through RTSP.

In July 2007, YouTube partnered with Verizon Wireless to enable mobile phone users to submit videos through Multimedia Messaging Service (MMS).

On July 23, 2007, and November 28, 2007, CNN and YouTube produced televised presidential debates in which Democratic and Republican US presidential hopefuls fielded questions submitted through YouTube.

In December 2007, YouTube launched the Partner Program, which allows channels that meet certain metrics (currently 1000 subscribers and 4000 public watch hours in the past year) to run ads on their videos and earn money doing so.

As of 2007, the  domain served as image hosting service, but was subsequently repurposed for shortening watch page URLs.

Around 2008, "Warp Player" was tested out. It was an experimental interactive interface for browsing videos, where links to videos appeared as thumbnails, visualized in a floating and navigable net.

Starting in 2008, the site featured a series of each year until 2016. At the first, on April 1, 2008, all video links on the front page were redirected to Rick Astley's music video "Never Gonna Give You Up", a prank known as "rickrolling". The other gags are covered in .

In June 2008, were introduced. Users were able to add text boxes and speech bubbles at any desired location and custom sizes in various colours, and optionally with a link and short pausing, allowing for interactive videos. In February 2009, the feature was extended to allow for collaboration, meaning uploaders could invite others to edit their video's annotations. On May 2, 2017, annotations were locked from editing, and on January 15, 2019, they were entirely shut down.

Since October 2008, deep linking to a playback position through a timestamped URL is possible.

As part of the "TestTube" program which allows users to opt to use experimental site features, a ''comment search'' feature accessible under  was implemented in October 2009. ''YouTube Feather'' was introduced in December as a lightweight alternative website front-end intended for countries with limited internet speeds.

In November 2008, YouTube reached an agreement with MGM, Lions Gate Entertainment, and CBS, allowing the companies to post full-length films and television episodes on the site, accompanied by advertisements in a section for US viewers called "Shows". The move was intended to create competition with websites such as Hulu, which features material from NBC, Fox, and Disney.

YouTube was awarded a 2008 Peabody Award and cited as being "a 'Speakers' Corner' that both embodies and promotes democracy".

In early 2009, YouTube registered the domain  for videos embedded on United States federal government websites.

In April 2009, YouTube launched their earliest HTML5 video player experiments.

Throughout 2009, the alphabetical sorting of YouTube's "AudioSwap" feature helped popularizing Alexander Perls' "009 Sound System" music project through frequent use in videos.

In June 2009, ''YouTube XL'' was launched. It was a front-end for viewing and browsing on television sets, and as such, for use on stationary game consoles with web browser, such as the Nintendo Wii. Its appearance varied depending on device.

In July 2009, developers of YouTube placed a site notice that warned about the impending deprecation of support for Internet Explorer 6, prompting its users to upgrade their browser. It is claimed that they represented 18% of site traffic at that time. Within months of the announcement, traffic from Internet Explorer 6 reduced to less than half, and traffic from other browsers surged accordingly. Support for its successor, Internet Explorer 7, was deprecated in the second half of 2012.

3D stereoscopic video was first implemented in July 2009.

In late 2009, YouTube introduced automatic captioning of videos through speech recognition. Initially only available in English, it was expanded to six European languages in late 2012.

''Entertainment Weekly'' placed YouTube on its end-of-the-decade "best-of" list In December 2009, describing it as: "Providing a safe home for piano-playing cats, celeb goof-ups, and overzealous lip-synchers since 2005."

The transition from ActionScript version 2 to 3 was initiated in late 2009.

In January 2010, an overhaul of the watch page was first tested as beta. It was made default on March 31st.

At a similar time, "YouTube Disco" was launched, a music discovery service. It closed in October 2014.

In January 2010,

Until then, a five-point video rating system that used star icons was in use. Users were able to rate videos with one to five "stars", where more indicated greater preference. This rating system was replaced with a bidirectional one using positive "like" and negative "dislike" ratings, citing low numbers of users rating other than the most (5) or least (1) stars. Ratings of three or more "stars" were converted to "likes" and such below accordingly to "dislikes".

Later the same month, the control section of the Flash-based video player was redesigned to feature a dedicated row for the seek bar, as is used since, as of 2021.

In May 2010, it was reported that YouTube was serving more than two billion videos a day, which was "nearly double the prime-time audience of all three major US television networks combined".

Around 2010, an easter egg of the Flash-based video player was discovered, where pressing the arrow key while the dotted loading animation is visible initiates a Snake game formed by the dots. The HTML5-based player, which initially had the same dotted loading animation, did not support it.

In September 2010, a unique full-page interactive TippEx advertising campaign was launched on YouTube, where the entire watch page was simulated in a Flash viewport. A hunter who does not wish to shoot a bear grabs outside of the video's viewport to reach for a Tipp-Ex tape roller, and uses it to cover the word "shoots" in the video titled "A hunter shoots a bear". Users were able to enter words in the gap, which lead to different unlisted videos with a multitude of pre-recorded reactions.

In October 2010, Hurley announced that he would be stepping down as the chief executive officer of YouTube to take an advisory role, with Salar Kamangar taking over as the head of the company.

James Zern, a YouTube software engineer, revealed in April 2011 that 30 percent of videos accounted for 99 percent of views on the site.

Live streaming was introduced in April 2011, initially rolled out to select users and later expanded.

In May 2011, YouTube reported on the company blog that the site was receiving more than three billion views per day, and that 48 hours of footage are uploaded every minute.

In June 2011, YouTube started experimenting with reaction buttons, allowing users to react to videos with a multitude of expressions, similar to Facebook's 2016 reaction buttons, though YouTube removed reaction buttons soon after.

Since July 2011, the word "YouTube" is placed after the video title in the watch page title, whereas before it until then.

During November 2011, the Google+ social networking site was integrated directly with YouTube and the Chrome web browser, allowing YouTube videos to be viewed from within the Google+ interface.

In 2012, YouTube reported that , and that around three-quarters of the material comes from outside the U.S.

As of 2012, users were able to rate playlists, and videos' view counts and playlists' total duration were indicated on playlist pages.

In March 2012, preview tooltips for the video player's seek bar were introduced on the desktop web front end, initially available on select videos and gradually rolled out. This feature allows the viewer to additionally preview portions of a video by hovering above the seek bar with the mouse cursor, whereas only the time stamp was indicated before. Dragging the position handle of the video player additionally showed surrounding preview images in a film strip layout. For videos longer than 90 minutes, a magnified portion of the seek bar was additionally displayed since to facilitate fine seeking.

On March 30 and 31, 2012, in the course of earth hour, the site used a light-on-dark color scheme (or "dark theme"). A switch was located left to the video title, allowing to toggle back if desired. This is the earliest known use of a light-on-dark color scheme on the site. The switch was removed the following day and the bright background was restored.

From 2010 to 2012, Alexa ranked YouTube as the third most visited website on the Internet after Google and Facebook.

In late 2011 and early 2012, YouTube launched over 100 "premium" or "original" channels. It was reported the initiative cost $100 million.

An algorithm change was made in 2012 that replaced the view-based system for a watch time-based one that is credited for causing a surge in the popularity of gaming channels.

In October 2012, for the first-time ever, YouTube offered a live stream of the U.S. presidential debate and partnered with ABC News to do so.

On , The YouTube slogan (Broadcast Yourself) was taken down due to the live stream of the U.S. presidential debate.

In October 2012, YouTube introduced the ability to add a translucent and overlayed custom icon at a corner of all own videos, which can link to the channel page or a specified video. The feature was initially named "InVideo Programming".

YouTube relaunched its design and layout in early December 2012 Notable changes of the watch page are the relocation of title and the "Subscribe" button from above to below the video's viewport, the removal of the button that opened a section above the video viewport showing other videos of the same channel without needing to leave the watch page, and the removal of a button-sized banner located above the viewport, which could contain a custom image, popularly icons and text logos.

On December 21, 2012, the "Gangnam Style" music video by South-Korean musician PSY became the first YouTube video to surpass one billion views.

As of early 2013, YouTube video recommendations contain both videos and channels.
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## 기능 축소
In early 2013, YouTube introduced a new layout for channels known as "One Channel", which added the ability to put playlists into shelves on the channel front page, but removed custom backgrounds. Formerly unified channel pages were separated into multiple sub pages such as "Videos", "Playlists", "Discussion" (channel comments), "Channels" (featured by user), and "About" . This layout was initially optional, with a transitional period taking place between March 8 and June 5 after which it has been made permanent for all users. Coarsely, this layout is still in operation as of 2022.

In March 2013, the number of unique users visiting YouTube every month reached 1 billion.

Automatically generated playlists known as "YouTube Mix" were first rolled out in April 2013.

Since approximately July 9, 2013, the first page of videos' comment section is no longer included in the watch page's static HTML source code, but instead loaded subsequently through AJAX.

A picture-in-picture mode for browsing within the app while watching was introduced to the mobile app in August 2013.

On September 12, 2013, the "video responses" feature introduced back in May 2006 was discontinued, citing a low click-through rate. It allowed users to respond to videos through a new or existing video which appeared above the comment section.

In the same month, YouTube's comment system on channel pages, and two months later on videos, was integrated to Google's social network site "Google+", since which a Google Brand Account is required to be able to comment. This change also included the ability to edit existing comments and include URLs in comments, with the removal of the 500 characters limit and negative user ratings from comments. Channels created prior as standalone YouTube accounts using its legacy registration form have been grandfathered to a  URL.

In November 2013, YouTube's own YouTube channel surpassed Felix Kjellberg's PewDiePie channel to become the most subscribed channel on the website. This was due to auto-suggesting new users to subscribe to the channel upon registration.

Users of the mobile app can reply to comments since April 2014.

In June 2014, YouTube replaced the classic Inbox feature with a new private messaging system, which – like comments – required users to have their YouTube accounts linked with a Google+ profile, which was subsequently moved over to Google Brand Accounts. Legacy Inbox messages could be viewed and downloaded up until December 1.

In October 2014, videos' frame rate limit was increased from 30 to 60, allowing for a smoother and more realistic appearance. It was initially only available with Google Chrome and later expanded to other browsers. 60fps are only available at 720p resolution and above.

In November 2014, YouTube launched a paid subscription service initially named "Music Key", featuring background playback, the integrated ability to download music for offline use, and no advertisement breaks.

Support for the dedicated YouTube application on the Sony PlayStation Vita game console was deprecated in January 2015, for the Nintendo Wii and Wii Mini in June 2017, and for the Nintendo 3DS in August 2019.

In March 2015, YouTube introduced the ability to automatically publish videos at a scheduled time,

360-degree video was launched in March 2015. A year later, in April 2016, the ability to live stream 360-degree video was launched. Additionally, live streaming resolution was elevated to 1440p and 60 frames per second, and support for the ''EIA-608'' and ''CEA-708'' formats were added for embedded captioning.

In August 2015, "YouTube Gaming" was launched. It was a separate web and mobile front end showing only gaming-related content, featuring a similar layout but somewhat modified appearance compared to the main site, and a light-on-dark color scheme well before the feature was introduced to the main site.

At a similar time, the view count indicator was patched to become continuous instead of temporary halting at 301 views (indicated as "301+") for hours, reportedly to calculate and deduct "counterfeit views". This phenomenon was first documented in June 2012. As an easter egg, the view counter of the video by mathematics channel "Numberphile" discussing this phenomenon was set to remain at 301.

In December 2015 and January 2016, direct uploading through email and webcam recording respectively were removed. The former existed to support cell phones with limited web browsing capabilities.

Around January 30, 2016, the dedicated "".

The earliest trials with a new channel sub page named "Community" as an impending replacement for "Discussion" were conducted on select channels in September 2016.

In November 2016, the ability to "heart" and pin comments under own videos was added. "Hearting" visibly marks comments under own videos to signify appreciation; a select comment can be pinned so to remain on top of the section.

Since December 2016, YouTube started rolling out a progress bar at thumbnails' bottom edge, indicating the watch progress of previously watched videos, starting with the iOS app.

Live streaming from the mobile app was rolled out in early 2017, initially only available to channels with at least 10,000 subscribers.

As of 2017, notes could be added to videos within playlists by the creator of the playlist.

In January 2018, a musical note badge replaced the check mark to denote account verification status for music artists. YouTube refers to such channels as "artist channels", a feature introduced months prior with a slightly different channel layout.

On April 3, 2018, a shooting took place at YouTube headquarters.

On July 9, 2018, the private messaging feature has been removed from "Creator Studio", purging existing messages.

In July 2018, it was reported that the site's "Polymer" redesign slowed performance significantly on non-Chromium browsers compared to the legacy, HTML-based version of the front end.

In August 2018, the search result counter resembling that of Google Search was removed. Whether it is related is unknown.

In October 2018, YouTube announced launching a fund program for educational creators, to which creators with a minimum of 25.000 subscribers and a demonstrated expertise in their field could apply through an agreement.


On the same day, the dedicated section for video credits like "Starring", "Written by", and "Edited by" was removed from videos' description box, citing low usage. Addition of such was already disabled since November 27, 2018, the same day on which the definite annotation removal was announced.

Dedicated "learning playlists" that do not include algorithmic recommendations, have a distinct page layout, and allow dividing videos into sub-sections of lessons, were introduced in July 2019.

Also in September 2019, the new "direct messaging" system was removed two years after introduction. This was a distinct system not to be confused with Creator Studio messages, which was removed in July 2018 after replacing the legacy Inbox feature – which existed since YouTube's early years – four years prior.

Another change reported in September 2019 was a strictening of the account verification procedure. Previously, the sole criterion for verification is said to have been a subscriber count of at least 100.000, whereas since, YouTube reports requiring what they describe as a "proof of authenticity", incorporating notability outside of YouTube. A change of the verification badge's appearance from a symbol into a highlighted channel name was also announced, but has not been implemented since.

In late October 2019, a list layout with snippets of videos' descriptions, slightly in resemblance of YouTube in its early years, was tested for a short time, then the shelf (or "grid") layout was restored.

In November 2019, YouTube has announced that the service would phase out the classic version of YouTube Studio to all YouTube creators by the spring of 2020.

In that month, a watch queue feature was added, which resembles the intermittently removed "QuickList" feature that was originally introduced in 2006.

In late 2019, the mobile website got equipped with a standalone HTML5 video player interface rather than displaying browsers' built-in HTML5 player.

Since December 2019, users are no longer able to share the automatically generated playlist of positively rated videos.

Beginning January 2020, video creators have to mark whether a video is made for kids or not, YouTube citing compliance with the Children's Online Privacy Protection Act as the reason for the change.

The ability to add polls with up to five options as video info cards was removed in May 2020.

The ability to visibly divide the video player's seek bar into chapters using time stamp lists in the video description was introduced in May 2020.

In June 2020, YouTube phased out the ability to use categories.

In August 2020, automated Email notifications of newly published videos by user-opted channels have been shut down, citing low numbers of users who open them. Only push notifications (mobile) and internal web notifications (desktop) of new uploads remained.

The "Community Captions" feature which allowed viewers to contribute captions for public display upon approval by the video uploader was removed in September 2020.

Since September 2020, YouTube blocks embedding of videos marked as "age-restricted", meaning deemed unsuitable for minors. Their preview thumbnails appear blurred in search results since October 2021.

YouTube launched a feature in live chat for chat streams where the creator can enable subscriber only mode.

In December 2020, comments on so-called "art tracks" which are automatically posted music tracks with album cover, frequently on "topic channels",

In July 2021, all unlisted videos prior to 2017 were set to private, making them unplayable except on channels whose owners intervened by manually opting out.

Around that time, a study conducted by web archivists has concluded that over half of the videos which were on air on the platform around 2010 were no longer available by 2021. Such videos were either reversibly set to "private" or irreversibly erased, the latter of which occurred for the majority of those videos. Videos are taken down as a result of individual policy or copyright violation, channel terminations, retroactive policy changes, and voluntarily by uploaders.

On August 24, 2021, YouTube sent a cease and desist to the developers of Groovy, a Discord bot which enabled audio from YouTube videos to be played in Discord voice chats, as the bot violated YouTube's Terms of Service.

In September 2021, the dedicated "view attributions" page was discontinued citing low usage.

In October 2021, YouTube experimented with indicating the most watched parts of a video through a solid line chart appearing on the seek bar in the mobile app to facilitate watchers finding relevant parts.

All channels' "Discussion" sub page is to be ultimately discarded on October 12, 2021. The feature was known as "Channel comments" in the site's early age, and served as channels' general comment section. Previously, it was gradually replaced with the that first rolled out to select channels, and since approximately 2018 to channels surpassing a subscriber count threshold that decreased over time, discarding existing discussions. During the same day, YouTube lowered the threshold to the Community page from 1000 to channels with at least 500 subscribers.

On November 10, 2021, YouTube announced the removal of videos' count for negative user ratings (also known as "dislikes" and "thumbs down"), reportedly to protect creators from online harassment. The dislike count remains solely visible to respective channel owners. This change was first tested with select users in March and again in July.-->

## 지역판 서비스
2007년 6월 19일 구글의 에릭 슈미트 CEO는 프랑스 파리에서 유튜브의 각 국가별 서비스, 즉 지역별 페이지를 출범 개시한다고 밝혔다. 이에 따라 유튜브의 인터페이스가 전세계 공통 서비스에 머무르던 것을 넘어서, 전세계 108개국과 1지역에 해당되는 개별 서비스를 개시하게 되었다.

각 지역판 서비스 개시일자는 다음과 같다.

유튜브의 각 지역판 화면 인터페이스는 유저의 IP 주소를 기반으로 제시된다. 어떤 경우에는 "This video is not available in your country" (이 영상은 당신의 국가에서 볼 수 없습니다)라는 메시지가 표시되기도 하는데, 이는 특정국에 따라 저작권 제한이 걸려 있거나 부적합한 콘텐츠를 담고 있는 영상일 시에 나타난다.

2007년 10월 17일 홍콩판 유튜브의 서비스 개시가 발표되었다. 당시 유튜브의 스티븐 첸은 다음 대상 국가가 대만이라고 밝혔다.

2008년부터 2010년까지는 튀르키예에서도 유튜브 접속이 차단된 적이 있는데, 사유는 건국의 아버지로 추앙받는 무스타파 케말 아타튀르크를 모욕하는 영상과 이슬람교 신자들에게 불쾌할 수 있는 주제들을 다룬 일부 영상에 대해 튀르키예 사회 내에서 논란이 불거졌기 때문이다. 

2009년 3월에는 유튜브와 영국 저작권 관리기관인 PRS 포 뮤직과의 마찰이 벌어지면서, 영국 내 유튜브 유저들을 대상으로 프리미엄 뮤직비디오 시청이 차단되는 일이 있었다. 양측의 라이센스 계약이 합의에 도달하지 못하면서 주요 음반사들이 게시한 영상을 삭제한 것인데, 2009년 9월 소강 상태에 이르면서 영상들도 원상 복구되었다.