Here’s a presentation the Google team actually gave on what search engine optimisation is:

If you want a more detailed page, check out our own guide to SEO for beginners.

We've recently updated our comments policy and increased the number of comments a visitor has to make to get seo friendly links in comment signatures to reward long term readers and make it a bit harder for dofollow spammers ;) - I told you dofollow spamming wasn't a long term strategy....