"The Internet is about to get a whole lot more collaborative," said Brian Heater in PC Magazine, "at least if Google has anything to say about it." The search and software giant is introducing a new feature, Sidewiki, that lets users post information or highlight text on any Web page. And it's releasing Sidewicki as a feature on the Google Toolbar for Internet Explorer and Firefox.

"It's unclear if the service will really deliver a lot of value," said Ryan Paul in Ars Technica. "After surfing around the Internet with it for a short while and looking at the annotations that have already been posted on popular websites, I have yet to see any that are really useful or substantive." Maybe most users just don't know what to post yet, so the quality of the Sidewiki content could get better.

Back in 2001, said Michael Arrington in TechCrunch via The Washington Post, a Web startup called Third Voice tried something similar, but website owners just didn't "like the idea of people 'defacing' their websites with comments they couldn't control." But that was another time—it's doubtful sites will have the same "visceral reaction" now. The real questions are "whether they can control spam, which has plagued SearchWiki," and how long it will be before Google puts ads in it.