In your account settings you are able to choose your default subscription options. Change it to what you'd like. If you're automatically receiving thread replies all the time, I'm guessing you accidentally switched the option at some point in the past. I don't think (I could be wrong though) that the default is to receive emails on every thread... Let me know if you need assistance with it.

The roster is due for a cleanup, yes. The new site won't have as many dead names on it, but may retain a select few for jobbing or other purposes. There are also some rules and information sections that are going to be brought up to date on the new site.