Just received same Postcard re: DELTA
Got the same postcard but this time using DELTA's name and logos and reference 2 Free roundtrips with Delta (3 Day 2 night free also) . Addressed to the name spelling I use on one of my credit cards, so best to go into Credit Cards and make sure you opt out of their being allowed to sell your name and address.
Also says in small print: "This offer is not sponsored by or affiliated with Delta Airlines but they are a major supplier. Taxes and reservation fees are the responsibility of the recipient."
Reservation Fee? haha...
same phone # 1-888-639-6990 (West Palm Beach permit 3950 Postage 1st class mail stamp)