Maybe I'm missing something here, but I don't see why this is "way overboard." Does your concern lie in the number of e-mails that would be sent, or what? I'm sure you're already sending a massive amount of e-mails for the "subscribe to thread" feature. Just to be clear, I'm not suggesting that the contents of a private message be sent to the user. I can see how this would turn the forums into a new free e-mail service. I'm merely suggesting that users be sent a simple e-mail that says they have new personal messages (similar to the subscribe to thread e-mail). Plus, I'm only suggesting that this be an option, so users could just turn it on if they wanted to use it.