These are quite interesting and I think the wave of the future.
A Wiki is a book written by a large number of contributors. Wikipedia.com is the best known example.
I am working on the development of an “open source” LSAT book. I just started this today, so you will find my beginning at:
In the interim, though I congratulate the following on their Wiki books:
General LSAT Prep Guide
Past LSATs Explained – Appears to be comprehensive