If you're looking for a way to start writing for money, Google as of today offers a new option.

Its new Knol - short for 'a unit of knowledge' - site is similar to Wikipedia in that anyone can write an article on (almost) anything. But where Wikipedia is a collective endeavor where anyone can both write and edit pieces, Knol focuses on preserving ownership of articles.

That ownership makes for two key differences when comparing Knol with Wikipedia. First, authors can choose 'Moderated collaboration' for their work, which allows them to vet any proposed changes to their article. And second, authors can opt to show Google ads, and thereby share in their revenue.

If you have a Gmail account, it takes about 30 seconds to start writing a knol. If you do, you can also choose open collaboration, where any signed-in user can edit the knol. And knols won't display revenue-generating ads by default. To get them, you'll need to create an AdSense account or tie in an existing account.

Google's announcement post says that the company expects "multiple knolls on the same subject, and we think that is good."

I'm curious to see where Knol will go, and whether anyone will make any real money from its ads. I disagree with TechCrunch's Jason Kincaid, who writes that the system will draw many posts on huge topics like Barack Obama, but fail to draw articles on less popular topics. It instead encourages the opposite, since a well-written post on an obscure subject would stand out much more than a me-too article on a politician. The authoritative post would stand a better chance of showing up in search results, and thereby drawing ad revenue, for a longer period of time.