Google has put out seven new Webmaster Help videos about various types of webspam. I'm not sure how long ago they were recorded, but they all just hit the GoogleWebmasterHelp YouTube channel, and feature Matt Cutts, and in some cases, Cutts and other Googlers.
Here's one on Unnatural LInks.
It's mostly pretty basic stuff about the difference between natural and unnatural links, but Google is using these videos in its documentation for its quality guidelines, so that makes a great deal of sense.
"The good news is that this is something that is fixable," says Cutts. "It's fixable by you relatively easily, if you decide to commit to it."
Sandy, the other Googler in the video, notes that removing all the unnatural links is not always the best option, as they only ask that they don't pass PageRank. This, of course, means nofollowing or redirecting through a URL that's blocked by robots.txt.
Cutts notes that he's a big fan of the removing all the links approach.