As seen on SE Roundtable, Google has made claims that spam links won’t hurt your rankings.
…I wouldn’t really worry about spam sites hurting your ranking by linking to you, as we understand that you can’t (for the most part) control who links to your sites. However, there is some action you can take if you come across spam in Google’s index. The preferred method of reporting spam to us is by clicking on “Report spam in our index” while logged into Webmaster Tools. If you don’t have a Webmaster Tools account, you can use our non-authenticated spam report form: http://www.google.com/contact/spamreport.html…
So all those dozens of spam-mish backlinks pointing to my site, they won’t hurt me? This is true, but you do indeed need to be careful about who you link to. I’m still trying to figure out a tool that can be used to qualify a site as being part of a “bad neighborhood,” but I haven’t found anything yet.
