Starwood Preferred Guest (SPG) and Emirates launched reciprocal elite benefits back in 2014 (read more here) where members can earn bonus Skywards miles and Starpoints among other benefits after linking accounts.
When I had a look at my SPG account this morning, there was a deposit of 500 Starpoints made yesterday implying that it was thank you points for having merely linked the accounts at some points in time (I have not taken advantage of the partnership).
You can access SPG Emirates Your World Rewards here.
READ MORE: SPG Rate & Bonus Points And Miles Promotions
Starwood has similar arrangement with Delta called Crossover Rewards and was supposed to launch something too with an airline based in China. Not sure what happened to the latter plan.
I certainly always take free Starpoints but not sure what these are for really. Cannot remember signing up for any SPG or Emirates promo that would have indicated points coming my way. There have been targeted offers for linking accounts and getting Starpoints in the process and I have written about them.