Search engine Land just posted Google’s Matt Cutts: I Recommend NoFollowing Links On Widgets.
Matt Cutts said, “I would recommend putting a nofollow, especially on widgets.”
If your a WordPress user, Semiologic's External Links plugin can accomplish this for you without the need to manually enter rel="nofollow" in all your outgoing links in your sidebar, header and footer widgets.
- Simply go to Settings->External Links.
- Check the Apply Globally box.
- Check the Add No Follow box.
- Save Changes and you're all done.
Pretty simple and best of all, automatic!
External Links is part of the Semiologic Pro package. You can also find it in the WordPress Plugin repository – External Links.