It was no secret that links from Wikipedia were weighted highly by Google. It meant that if a site was linked from Wikipedia, it had a greater likelihood of appearing higher up in the search results page of Google. Due to excessive spamming, Wikipedia announced that they will adopt the ‘rel=”nofollow”‘ for links within en.wikipedia.org (see article by SEO Roundtable).

It will be interesting to see how this will affect the search engine optimisation and marketing strategies. BTW, in early 2005 Google came up with the rel=”nofollow” tag to combat comment spam.