CNet follows through on it's earlier story regarding "editorial" issues at Wikipedia - this time looking at the libel angle. At the end of the day though, Wikipedia appears safe from claims:
Thanks to section 230 of the Federal Communications Decency Act (CDA), which became law in 1996, Wikipedia is most likely safe from legal liability for libel, regardless of how long an inaccurate article stays on the site. That's because it is a service provider as opposed to a publisher such as Salon.com or CNN.com.
This is also the same for a TypePad - but it isn't the same for an individual blogger.