A new Google Toolbar feature allows web users to read and comment on any and every web site. The feature is called Google Sidewiki and is available for the Firefox and IE versions of the Toolbar.
Unlike blogs, the most recent comments won't appear first. Instead, Google has, of course, developed a ranking algorithm to place what they deem the most relevant comments first.
Right now, very few sites have comments on them. Hopefully, as time goes by, there will be more useful content.
Oh, I almost forgot to mention. Remember how Google always releases something big right after a major announcement by a competitor? Well, this is probably their answer to Yahoo's new search update from yesterday.
In the meantime, check out this introductory video, go try SearchWiki for yourself. Then come back and leave us a comment, letting us know what you think.