The PI's John Cook offered the best short summary of what's new at Zillow in his Venture Blog today:

Big changes at Zillow.com today, with the company overhauling its Web site to include user-generated for sale listings, a real estate wiki and a new service called "Make Me Move" that allows any home owner to set a dream price for their home on the site.

You can get more sober and insightful discussion from Zillow's blog, of course, but we've enjoyed reading some of the more biased (and either worried or thrilled) commentary.

Greg Swann at bloodhoundblog offers topic-by-topic analysis of What It All Means for the real estate market:

We are looking at the embryonic form of a de facto national MLS system. There are wrinkles, and we’ll get to them, but there are two things that Zillow.com has by now proved itself eminently willing to do that both the National Association of Realtors and Realtor.com have proved themselves eminently unwilling to do: Change and grow. Zillow may not be the last word in this story, but it has written two very compelling chapters already this year.

Galen at Rain City Guide, on the other hand, suggests a devious new prank:

Mix Zillow’s amazing capacity to quietly market itself and its new feature (list your home on Zillow, FSBO or FSBAgent) and you have a great new service for driving traffic… to your annoying neighbor’s house. List their house at 25% below Zillow’s estimated value and invite people to come by to see the place anytime after 8 on weekdays. You could alternately ‘claim’ their house and hold it until they decide to sell, at which point you get to choose the price, at least on Zillow. To be fair, listing someone’s house has always been possible on Craigslist, but you never had to send in proof of ownership to be able to reclaim your house from them.

What it all means for local DIY home-sale site Redfin we don't know. But those nasty people next door? Boy, have we got a monkey wrench for them...