Google's Knol wiki came out of closed beta this week, prompting a lot of speculation that it was launched to compete with Wikipedia. For PR people, it looks like a how-to version of HuffingtonPost and their massive stable of contributors, providing experts--and the PR people who represent them--a great vehicle for positive search results.

So far Knol is not a serious search challenger finds Alley Insider, but if you're a guy who knows how to read Russian, it's pretty damned effective.

Unlike the surreptitious efforts of some on Wikipedia, eKnol is about transparent authorship. Other people can suggest edits and you can accept or ignore, and the person won't be notified of your decision as CNET's Elinor Mills explains in her own test run.

The real competition could be to vertical trade publications with expensive walled gardens, relied upon by PR people for years for those high-end bylined articles by clients.