What is a SEO?

My buddies from the UK, South Africa, Holland, and Belgium are all SEO people and I never really knew what that was until I came to this conference. They are search engine optimizers and work for their clients to increase traffic to their sites. There are about 7 or 8 of those type here at Search Champs. They are very interested in adCenter and how to use MSN Search to optimize for their clients.