Nowadays everyone has 5 to 10/15 profiles on different web sites.
The sites I use more are these
Pownce: http://pownce.com/smnbss/ (Pownce will be shutting down on Dec 15, 2008)
As per Google Algorithm definition
“The fact is that PageRank is based on incoming links, but not just on the number of them. Instead PageRank is based on the value of your incoming links. To find the value of an incoming link look at the PR of the source page, and divide it by the number of links on that page. It’s very possible to get a PR of 6 or 7 from only a handful of incoming links if your links are “weighty” enough.”
Type an quality of incoming links are very important on page ranking, so my idea is to start to cross reference my profiles via links on profile description so that everyone of my profile pages will help the ranking of the others at least for my username, name and surname keywords.
This is in fact part of my experiment 🙂