Slate thinks so, as of 2008:

  Even after allowing for discounted entry fees, the back of
  the envelope says the Webbys could be taking in more than
  $2 million from its contestants.

http://www.slate.com/articles/news_and_politics/press_box/20...

There might be sponsorships, and I think they also sell additional merch, and maybe tickets to the awards event. It's probably not cheap to organize.