I think I was a member of Readerville, but I never participated there. But any site that promotes reading and books is a good place, in my opinion, and so I'm sorry to hear of its demise.
For the past year, I've been participating in Bookballoon, which is something of a spinoff of Readerville (since the founders of the former were active participants in the latter). Bookballoon's Gary Glass has this comment: Readerville, Adieu.
I'm not sure I would want to be a member of more than one such site, but I am grateful for Bookballoon, and enjoy the discussion of books there. If you are bereft by the loss of Readerville, but just like the idea of discussing books with like-minded folks, give it a try.