Today, a video was released starring Matt Cutts, who heads up the Search Spam of Google, stating that links that are nofollowed won’t hurt your rankings in Google.

Most of the time, nofollowed links usually won’t affect your rankings on Google negatively.  With that being said, Google did say that Google will take manual action on your links if they find that you are mass spamming on a huge scale, regardless of nofollowing.

Normally it seems like common sense that if you spam enough, Google will catch you, but apparently some spammers need more than just common sense.