I have created the user Retag, you can see my name there, but I will add a link to my user page.
I have created it since it doesn't feel good when my name is all over the front page just because of retagging question while I haven't added any new information to those questions.
We have filed a feature request to SE that ratagging should not bump the questions to the top or at least the name of the last user performing a significant edit should be displayed on the active questions page but they haven't been accepted.
I think we should at least get an interesting questions page like the one on SO on cstheory (if we have to leave with properties of SE system that we don't like because users on SO and other SE site like them (to keep the system uniform), then we should also get this useful feature on cstheory too).
About multiple accounts, we haven't had a policy on cstheory AFAIK, don't know about the general SE rules.