Yesterday I received a very fancy ivory envelope from DL by snailmail. It was an offer to join SPG at the Gold (mid) level, credit qualified Starwood spending for DL SkyMiles at three miles per dollar, and receive 3,000 bonus miles after three nights by the end of August, up to 9,000 bonus miles. You must sign up with spg.com using the "unique confirmation code" given on the enclosed "RSVP" card--don't throw away the smaller stiff card included in the mailing. There's language excluding combinations with other promos unless explicitly announced. (Note that these are not MQM or status miles.) To maintain Gold, you must qualify by the standard terms, which means ten stays or twenty-five nights normally (less for SPG AmEx cardholders) by the end of the year. Miles earned this way cannot be converted back to SPG points. Note that as SPG Plat, I normally earn points equal to three times qualifying hotel spend (not including taxes and certain charges), plus various promo bonuses. I consider one SPG point to be worth more than one DL bonus mile in general. My recent redemptions on DL (for SQ FC award tickets) and SPG (at the pay four and sleep five minus my 25% off award cert earned in a promo last year for the W Hong Kong) have been valued at very roughly ten cents per mile and six cents per point respectively, although I do not expect to ever again find such valuable uses of DL miles.