But how would a yahoo or gmail or other free account not be an actual email address? I think I know what you're saying, that it's not the email account with your ISP. But in addition to my ISP account, I have 3 yahoo, and 2 gmail accounts; all "actual" accounts that I use for various things. One is used specifically for occasions where I'm required to give an address, but I expect it might generate spam; I can just close it and open another if it gets too bad. Another I use for things like PerlMonks, where I do want an ongoing relationship; but if it did start accumlating lots of spam, it wouldn't be the end of the world to close it and get another.

I don't think you need to worry about it being what you call a temporary account; I haven't gotten any email from the site yet. I don't think you'd be "cheating their system" using a free acount.