martinibuster - 9:12 pm on Feb 3, 2009 (gmt 0)

I agree with JohnRoy about diversification. Virtually every time someone comes to me because their site is bouncing in the SERPs and can't hold on to their spots, it's because of a lack of diversification.

In my experience it's good to mix up the communities from which you're receiving links. Over the years the rankings tend to remain stable, rock solid. Every site that has backlinks is a part of a community because they are linked to other sites that link back to each other, thus forming a community.