Man, I just can't see this program being too great, the entire reason being that you're running it off of webbrowsers. That makes proxy support extremely inefficient, and it completely prevents high level multithreading. So, if you're trying to make 100 accounts on 4 different sites at the same time, it's going to take an hour or more, whereas using webrequests it would take a matter of a minute or two max simply because of the multithreading aspect. Is there a certain reason you're using webbrowsers? Look forward to seeing the program, going to start on my own version of this though, see what I can come up with.
Not trying to offend or anything, of course, just wondering why you would use webbrowsers over webrequests.