American Airlines has 5 separate e-newsletters, and they’re offering a new promotion where they’ll give you 500 miles for each e-mail you’re not currently receiving that you opt into.
Sadly, I was already subscribed to all of them. I think I’ve gotten miles for this in the past. The lesson from the old days, when e-mail signup bonuses were commonplace, was to never accept an email subscription without getting miles for doing so. Offers are far fewer these days, so when something like this comes along jump on it. And a spam-collecting address from Yahoo, Hotelmail, etc. is always useful in this regard.