Search Trends - Search Engine Marketing

My buddy Ryan McCoy wrote an interesting post about how Google tracks multiple sites from a single webmaster. I don't think Google necessarily cares about how many sites you have, but as Matt Cutts pointed out at Pubcon, they do have tools to quickly and easily figure stuff like that out and if you've got overlapping (or duplicate) content across multiple domains, it could be a problem. He goes on to ask the question of if/how Google is profiling website owners using Whois data and other resources. It has also been discussed whether or not Google can access private domain registration data. I don't think they can, but most site owners that have a lot of sites leave on obvious trail that doesn't take a rocket scientist (or google engineer) to figure out.