Here are two suggestions for Google’s GMail.
If there are multiple emails do you have to keep adding the signature at the bottom every time? Can’t you do some pattern matching and only put it there once. Or how about adding a signature shortcut key? Or hey since I can have multiple email addresses how about multiple signatures?
Gmail also has hands down one of the best spam filters. If you sign up for Google Apps it’s $50 a user, which is about the price of spam filter software from Norton and McAfee, Since Gmail spam filter is better and you get extra stuff, I’d use that as a selling point. They say it takes 3-5 seconds for a person to process an email and decide if it’s spam or not. Think of the time you’d save and the productivity increase you’d get if you had to evaluate half as much spam every day?