The game calculates a "goodness" score for each game played to decide which games should show up as a featured spectator game in-client, which is exposed publicly. Because this score is based on how good the players in game are, it's possible to roughly determine the average Elo of the players in a ranked or normal game. As this value is presumably calculated from the actual MMR, it's totally different from LKS.
Anecdotally, it seems quite accurate to me, just looking at changes in my normal Elo. I consistently lose/gain around 10 elo for losses or wins, and it's around where I'd expect it to be.