Given the question: I know that the answer to the question "How have celebrities latched onto YouTube?" is in "Both private individuals and large production companies have used YouTube to grow audiences. Independent content creators have built grassroots followings numbering in the thousands at very little cost or effort, while mass retail and radio promotion proved problematic. Concurrently, old media celebrities moved into the website at the invitation of a YouTube management that witnessed early content creators accruing substantial followings, and perceived audience sizes potentially larger than that attainable by television. While YouTube's revenue-sharing "Partner Program" made it possible to earn a substantial living as a video producerits top five hundred partners each earning more than $100,000 annually and its ten highest-earning channels grossing from $2.5 million to $12 millionin 2012 CMU business editor characterized YouTube as "a free-to-use... promotional platform for the music labels". In 2013 Forbes' Katheryn Thayer asserted that digital-era artists' work must not only be of high quality, but must elicit reactions on the YouTube platform and social media. In 2013, videos of the 2.5% of artists categorized as "mega", "mainstream" and "mid-sized" received 90.3% of the relevant views on YouTube and Vevo. By early 2013 Billboard had announced that it was factoring YouTube streaming data into calculation of the Billboard Hot 100 and related genre charts.". Can you tell me what it is?
The answer is:
at the invitation of a YouTube management