You mayn't know that I'm on Shelfari, as Auntie Nanuuq and I am an Administrator of two different groups:
Book Chat & Historical Mysteries. Both groups are "open" groups and you'll need no invitation to join.
In Book Chat: https://www.facebook.com/events/211987512286509/
we read most everything and anything. We have no limitations and everyone** is welcome. We have several ongoing threads: the monthly What We Are Reading, Hello My Name Is, and What Makes You Happy.
At the current time (June & July) we have a challenge: TBR (To Be Read). We are taking one book from several members TBR or Wish List and we are reading & rating them. Some of the more ambitious members (such as myself) are adding reviews as well. There will be prizes at the end of the challenge.
In April & May we had a "Scavenger Hunt": this was much more grueling, we had a long list of words (each w/ varying amount of points) and cover images to locate in the books we were reading. At the end there were also prizes.
Also in May we had a Historical Mystery challenge: the person reading, rating, & reviewing the most Historical Mysteries won a historical mystery.
In Historical Mysteries: http://www.shelfari.com/groups/34192/about
we focus on reading Historical Mysteries, but we also have a thread for What Else We Are Reading.
We have similar threads to those in Book Chat and a "Buddy Read" where we take turns picking an author or Historical Mystery series and then read, rate & review those books as well. We are currently reading the Benjamin January series & Abigail Adams series by Barbara Hambly/Hamilton.
We just finished an Agatha Christie challenge: the winner received a copy of one of Christie's favorite books, "Crooked House", the 2nd & 3rd place runner ups won handmade bookmarks.
Our goal in both groups it to promote the enjoyment of reading, sharing what we've read, and make new acquaintances & friends.
** In both groups we welcome Authors who are actively taking a part in the group. If you are there merely to promote your book, don't bother to join, we consider joining us for the sole purpose of promoting yourself & your book as "Spam", and we take steps to remove offenders from the group...
So, please drop by, peruse our groups, and feel free to join us!