Angelo co-founded DeviantArt at nineteen, but it was not his first company. Four years earlier, he started a music file-sharing site called Dimension Music. He sold it to Michael Ovitz in 1999, coming off of his stints at Disney and the Creative Artists Agency. Angelo worked the next two years at Ovitz's Artist Management Group & Lynx Technology Group (Ovitz's Internet investment arm) where he advised on how those companies could best strategically integrate the opportunities from emerging commercial applications of the Internet.
Angelo co-founded DeviantArt with Scott Jarkoff, Matthew Stephens and others that had the same background in application skinning community, with an initial budget of US$15,000.
As of 2017, Sotira is a member of the Wix management team along with all the other DeviantArt employees after Wix acquired DeviantArt for $36 million.