It has been a hot topic for a while now, yet many domineers aren't overly active in the SEO space. Yet.
Domaining is when you register a domain, or buy a domain on the seondary market, with the intention of deriving traffic, and turning that traffic into revenue. Traffic comes from type in traffic. i.e. people type a keyword into the address bar and add .com on the end. Domains can be valuable internet real estate, because, unlike a search engine, there is no middleman between you and the visitor. A lucrative pursuit, if you choose the right names.
Let's take a look at how domineering strategy can be applied to SEO.
Background
Aaron has a great interview with Frank Schilling. Frank is one of the biggest domaineers on the planet, and an articulate advocate of this strategy.