Well, they're back and claiming patent infringement on three more studios. This time, though, the studios are all small indie developers including Starpires developer Bad Pug Games, Minions of Mirth developer Prairie Games, Aces High developer HiTech Creations, and A Tale in the Desert developer eGenesis. The patent infringement claim centers on U.S Patent 8,180,858: "Methods for Presenting Data Over a Network Based Network User Choices and Collecting Real-time Data Related to Said Choices," which is the same patent infringement claimed against Turbine.
Each letter looks to have been sent out on or around July 1st of this year. No word yet on any legal developments beyond these letters.
[Thanks for the tip, Avaloner81!]