Mrs. Grundy writes "Wikipedia has started automatically adding rel="NOFOLOW" to all external links in an effort to combat link spam. Since wikipedia pages are hip-deep in high page rank they attract the unsavory sort of character hoping to gain a little love from Google on their coattails. By making pages NOFOLOW they essentially deny conferring any page rank points from google and hopefully reduce the incentive to spam the pages with offtopic links. This topic has come up before and the community voted to remove the NOFOLLOW business in 2005. Will this move actually reduce link spam or is even the potential clickthrough valuable enough without the boost in Google's ranking? And how does the value of ranking sites based on links change as more and more popular sites start tagging (eh...labeling) their links NOFOLLOW?"