Just dug out this video from SEO Moz. Its about correlation and causation in SEO. They make some very good points about what factors have a positive effect on SERPS. They is some interesting stuff about backlinks, they kill the myth about number of links being more important than themed links from good community related sites. The part at the end about no follow is also interesting. Just thought people might find it as interesting as I did. http://www.seomoz.org/blog/whiteboard-friday-correlation-causation-seo]
No worries the white board friday videos are always interesting, worth bookmarking them and coming back to them each week. One thing I have learnt about SEO is that you can never stop learning.