If you use (or plan to use) Wordpress blogs and are interested in SEO tips then this is a fantastic video that you should watch.
Matt Cutts from Google shares some really great tips about how the search engine works and how we should blog to get best results.
He goes in depth on the backlink obsession factor, page rank, site content, link juice and other relevant terms in this video.
If you do any sort of SEO work I recommend you watch this video.
