I’m really annoyed at sites like tribe.net & google AdSense which use an email address as the login and don’t let you change it. Assuming that an email address won’t change is just plain stupid. Most sites such as Amazon do let you change your email address.
I’m trying to get rid of my onepost.net address since I get far too much spam there. I used that as my public address to sign up for most websites. I expected that address to eventually become useless due to spam & I have several other backup addresses + my real addresses which I use very cautiously.