Google has done it again, this time with the launch of an update to the Google Toolbar browser plugin for Firefox and Internet Explorer called Google Sidewiki.

Essentially, Sidewiki allows visitors to submit comments and content related to any given web page as the navigate the page.

Jeremy Owyang gives a great roundup of the new SideWiki platform over at his Web Strategy blog.

Danny Sullivan at SearchEngineLand also does a great job of describing the new platform and how it functions.

This is potentially a game changer, and one that marketers need to prepare for as the web becomes even more democratic.

UPDATE: Kalena Jordan at SiteProNews writes a great review of Sidewiki.