In an interview over instant messenger with CNET News.com on Monday, Frankel said the time was right to step down after shepherding the latest version of the player, Winamp 5, to a public launch in late December.
The announcement brings to a close a chapter in the annals of dot-com history, which began in 1999 when the then-20-year-old Nullsoft founderin a deal reportedly worth $100 million. In the years that followed, Frankel clashed frequently with his corporate handlers, stirring up controversy with a string of products that fell outside AOL's approved regime.
"It was a pretty big love/hate relationship for me," Frankel, 25, wrote. "The love ultimately comes down to working with your friends on interesting things that you've poured a lot of time into. The hate is dealing with the process and the pitfalls of corporate America."
AOL spokeswoman Ann Burkart confirmed Frankel's resignation but declined further comment.
The resignation, quietly made public in online postings late Thursday, comes just weeks after , including at least two from the San Francisco-based Nullsoft division where Frankel worked.
Nullsoft operated in relative autonomy as a cutting-edge development arm for AOL. The team created the media player in AOL's flagship service as well as a streaming media technology called Ultravox that is now being used in AOL's broadband radio product. But the corporate culture of AOL never completely gelled with Frankel's more subversive side.
Frankel's most notable run-in with AOL occurred in 2000, when he posted a peer-to-peer file-sharing service called Gnutella. The software sparked an immediate response from AOL executives who were in the midst of acquiring Time Warner, which ran a major record company. Gnutella was eventually pulled, but not before thousands of copies were downloaded by other software engineers, spawning a new breed of file-swapping services that rose up after courts shut down Napster.
Time Warner has since agreed to sell Warner Music Group, citing sagging revenue and lackluster growth.
In May 2003,, which let users set up private networks equipped with peer-to-peer file sharing and instant messaging. Soon after Waste was pulled, but later to help complete the .
"I really had been putting it off long enough; it was just that time," Frankel wrote Monday. "Launching Winamp 5 was a big goal of mine for the last nine months, and having it out in the wild made it that much easier to move on."