You might read this thread since it appears that delta is offering a card with up to 50,000 points (25k for sign up plus $25k if you spend $10,000 total in the first six months). That would give you 25k regardless, and if you happen to spend $10k on the card, then another 25k:
http://www.flyertalk.com/forum/miles...edit-card.html

I believe that in general most people in this forum that apply for major credit cards online feel that it is fairly safe. But there are very good odds that if you can find the offer code for the card, and the phone number for customer support that you can call and apply via phone if that makes you feel better.