Why He Matters: People love to hate Calacanis, but it's hard to dispute that he's an expert at generating buzz. The creator of Weblogs Inc. -- an early blog network that he sold to AOL in 2005 -- recently launched the human-driven search portal Mahalo after leading the media on a merry chase to guess what the site would actually do.
But when Calacanis talks, people listen. And now that he's joined forces with Silicon Valley's leading venture firm (see No. 4) to fund Mahalo, many are eager to see what he'll do next and who he'll antagonize in the process.