African American Literature Book Club calls itself "the most popular website dedicated to Black books.
Bookreporter.com the Online Community for Book Groups
SWIFT Titles available in multiple copies for book clubs.
eVolver - The Denver Public Library website for Teens
GuysLitWire - contributed to by local librarian Becker
Reading Rants! Out of the Ordinary Teen Booklists
Favorite Teen Angst Books from the Grouchy Cafe
I haven't been able to find any sites about Readers' Advisory for Sensational Seniors, but there MUST be more than just Large Print and Audio Books out there for them!