From DomainTools, Mike Mann just announced the purchase of SEO.com by WashingtonVC.
Interesting strategy...spend big $$$ on the top SEO domain name and, only after the purchase, go form a SEO company. Welcome to the Age of the Domainer.
As a point of reference, porn.com sold for $9.5 Million recently.
[update by Aaron: after speaking with Mike Mann about the purchase, I agreed to update this post, noting the $5 million posted in the original title was inaccurate. ]