This appears to be for any Mileage Plus VISA, and there are a bunch of different ones out there.
Essentially, register to receive text messages and receive 500 miles. I don’t believe this is targeted. You’ll also receive text messages with bonus offers. No idea if these will be valuable. The ones that UA sends out with their TopGuest check-ins are pretty blah.
The terms say 6-8 weeks for the points to post, but it’s unclear if you need to stay registered that long. I just signed up, so I have no idea how many texts I’ll get. I generally find this type of stuff annoying, but I’ll bite to see what the text traffic is like.
Also, the link has been a bit wonky. I went to post this a couple days ago but the link wasn’t working. It seems to be working reliably now.