In many cases to date Google has argued that it is not responsible for the content it refers to from its site; and apart from a quick backtrack on publishing rights, has largely escaped unscathed. However, more and more cases are being brought against their video division, YouTube, with cases being brought against it by parties as disparate as a Brazilian model and the NYC Transit Authority.
The Saddam hanging film probably hasn't done the UGC industry any favours either and my guess is that it won't be long before the FCC starts taking a long hard look at this state of affairs.
It is somewhat ironic that this totally unregulated service and others like it came away scott-free in the recent EU review of online services, whilst traditional (and more responsible) media organisations are increasingly hamstrung.
As happened with Microsoft, a few legal actions are nothing more than irritating flies to swat to a mammoth like Google, but with the ubiquity of video cameras expect the policing of online video to become a hot issue.