I guess a period of one month with both active and mostly constructive posting should give you the ability to join most of the signature campaigns.
It's also worth mentioning that It's impossible to delete your account, If you don't want to use it anymore, simply change it to a hard password and forget about it and make a new one.
So you say a month of constructive posting will be enough to join , let's say lutpin and Yahoo's campaigns? That is a rather good news, actually I really like my username and wanna stick with it and my rank. Also I have pretty constructive posts in the past, I think.