It didn't get lost in the upgrade it got unstickied because of lack of interest.
The last book we read was 19 Minutes. About 4 people contributed to the discussion.
The way we used to do it was select a book by the 15th of the month and post a review and maybe some bookclub questions to ponder on and then on the 1st of the month we would open up a thread for discussion.

If you go to the last pages of the thread list for this forum you'll find the discussions so you'll have some idea of how they worked.