Periscope

Periscope is a live-streaming service similar to the likes of Justin.tv (and its Twitch.tv successor) which has been around since March 26th, 2015, with a strong focus on mobile devices. A short while before it launched, Twitter bought it.
== Shutdown ==
Twitter announced in a post on Medium on December 15, 2020 that it would be discontinuing Periscope at the end of March 2021, in favor of its own on-platform streaming which was introduced some time after Periscope's launch. Much like what happened with Vine after Twitter bought and killed that, content already shared with Periscope will still be available; however just like Vine, it may become increasingly harder to find without direct links as time goes on.
Periscope Community,
Today, we’re sharing that we have made the difficult decision to discontinue Periscope as a separate mobile app by March 2021.
First off, we want to be transparent about why we’re making this decision, especially to those of you who are active and passionate users of Periscope today. The truth is that the Periscope app is in an unsustainable maintenance-mode state, and has been for a while. Over the past couple of years, we’ve seen declining usage and know that the cost to support the app will only continue to go up over time. Leaving it in its current state isn’t doing right by the current and former Periscope community or by Twitter. We still believe in the power of live video to solve impactful problems, which is why we’ve brought most of the core capabilities of Periscope into Twitter. We probably would have made this decision sooner if it weren’t for all of the projects we reprioritized due to the events of 2020. We’re sharing our decision with you now because we want to be transparent and honest about where we’re at and what’s next.
We’re planning to remove Periscope from the app stores by March 2021, but no one will be able to create a new account in-app starting with the next release. Broadcasts that were shared to Twitter will live on as replays, and all broadcasters will be able to download an archive of their Periscope broadcasts and data before the app is removed in March 2021. You can find more info here about what will happen to your Super Hearts and broadcasts, how you can go live on Twitter going forward, and more.
Although it’s time to say goodbye, the legacy of Periscope will live on far beyond the boundaries of the app itself. The capabilities and ethos of the Periscope team and infrastructure already permeate Twitter, and we’re confident that live video still has the potential of seeing an even wider audience within the Twitter product.
Most importantly, we’re so grateful to all of you who invested time and energy into making Periscope the place to show what’s happening in your world and creating vibrant communities. We’ve learned so much, shared incredible experiences together, witnessed unforgettable moments in history, and seen pockets of the world we could’ve only imagined when we first launched Periscope. It was a genuine honor to pour our heart and soul into building something that other people loved enough to use and build their own communities around. Thank you so much.
Much love,
Team Periscope
Twitter's "Periscope FAQs" page mentions March 31, 2021 for when Periscope will be tossed into the bin alongside Vine.https://help.twitter.com/en/using-twitter/periscope-faq