Well...
Spoiler:
There is a reference to the location of Sorshen's (the Runelord of Lust) tomb in the Guide to Korvosa
Spoiler:
Some of Sorshen's stuff is going to be of some importance in Curse of the Crimson Throne, especially in the last adventure.
And it's not her super-sized calender of extreme explicit nude pictures of herself having fun with some of her pleasure slaves.
That's the secret christmas gift for this year's christmas for charter subscribers. You didn't hear that from me