On Monday, I received the usual congratulatory email from Delta for an "upgrade" to the same seat I got shortly after booking a flight via Expedia a couple of weeks ago. Yesterday, I received an email from Expedia entitled "Flight Upgrade for AYSK UADL" and, lo and behold, I had been upgraded to First on that flight (tomorrow). Interesting that Expedia found out about the upgrade and told me, while Delta only sends me spam about "upgrades".