Ok because it provides you support to share revenue whereas wikipedia doesn't provide it.

So knol will be the better option if you have adsense and want to share information with public.

I'll admit that upon launch, I dismissed Google Knol as a Wikipedia ripoff, and proceeded to ignore its presence shortly thereafter (amusingly enough because it NEVER appears in google search results despite conspiracy theories at launch.) Given some recent criticism in the blogosphere (must be a lazy news day if a quick search of your name on a web service and a few snide remarks about what you find is a blogworthy).

So, I checked it out a little further today, and I'll conclude that although it's nowhere near this reality yet, if google continues to resource it, I think Knol could be a powerful opinion-centric alternative to Wikipedia's encyclopedic approach, and ultimately the two will complement each other nicely.

Here's a quick overview of how I think the two services are different:

Wikipedia focused on creating individual and unique pages about everything in a massive heirarchy that are subject to changes by anyone who cares. Their crowdsourcing model requires many compulsive "experts" in pure egoless collaboration mode. Additionally the broader site requires heavy moderation to prevent people looking to game the system from being successful. It's also worth consideration that having canonical items dramatically simplifies site search for Wikipedia.

Knol's approach seems based on the fact that Google is not subject to these same limitations when it comes to search. Additionally, trying to lure committed Wikipedia users over to a redundant service is a slow, and difficult process. To differentiate, Google Knol allows varying degrees of ownership over the Knol pages (via creative commons) and many granular levels of editorial control for the owner. You can choose to make your page a total free-for-all (which may be great for traffic, but not so great for content quality), allow edits moderated by you, or prevent any edits from occurring at all.

This creates more of a small-picture payoff for individual contributors, which may prove out to be more attractive to a broader userbase than Wikipedia's selfless expectations. On a more narcissistic note: contrary to the terms of service on Wikipedia, it looks like there's no rule against creating a Knol about oneself.

One pretty major complaint: i did a quick search in Knol and the results seem to sort exclusively based on most recently edited knols (completely ignoring quality of content or user ratings). This is a failure that google should address. I know it's expensive and all, but can't Knol afford google sitesearch? :P

Apparently Google has gotten sick of Wikipedia showing up in its search engine for every query.  To add insult to injury, Google does not make any ad revenue from Wikipedia.  To combat this issue, they have announced (but not yet launched) Google Knol, which will let anybody write authoritative articles on any subject, and share ad revenue on those pages.  The good articles will presumably show up high in Google search results.

I think this is a pretty good idea, but a couple of years too late.  Squidoo has been doing this for a while.  Blogs let you do this as well.  To me, this sounds like a recipe for an unprecedented spam attack by folks who think that Google hosted pages will get special privileges in the search results.  

My personal feeling is that only a tiny percentage of people will want to write in depth, authoritative articles.  It's much more manageable - and fun - to say, rate and review things.  If only there were a site like that.