Most .Mac users may not have noticed, but mail aliases are available for use through .Mac’s webmail interface. You choose another email address (firstname.lastname@example.org) and all mail to that address goes to your existing account.
The primary purpose for this feature is fairly obvious. It allows you to have “throw away” addresses to use in situations in which you don’t trust the entity you are giving your email to. If you begin to receive a lot of spam through that address, you simply disable it. Other services have had this for a while, but it’s a welcome addition to .Mac’s existing tools. .Mac’s web-mail also color codes incoming email according to the alias address they came in through (very nice). It’s finally being exposed by websites like MacFixit. I actually discovered this gem several weeks back and never thought to tell anyone about it. .Mac’s documentation actually makes no reference to it.
This is also a way for you to get an address you wish you had chosen when picking out your .Mac username (as long as another user hasn’t already chosen it). The less popular .Mac is, the more aliases are available for use, so personally I don’t care if other people don’t find it too expensive.
The only gripe I have left for .Mac (and the email component in particular) is the amount of space allotted. Given, 15 MB is plenty, but I’d like to have the capacity to continue to store all my mail on the server without periodically archiving old mail. I certainly wouldn’t complain if they bumped it to 100 or 50 MB.