I together with my colleagues have launched
Bookvibe - book discovery and recommendation site, that shows you great books your friends and other people on Twitter are discussing. You can subscribe to weekly email, if you want books you'll love sent to your inbox.
http://www.bookvibe.com
Let me give an example how Bookvibe
helps you as a reader. It works for any Twitter handle (yours, your friend, author), but let's imagine that you are interested in Stephen King books:
1. Do you know that
Stephen King on Twitter follow only 19 people. It might be interesting to know what those people are saying about books, right? Here you go:
http://www.bookvibe.com/people/steph...?scope=friends
2. Do you want to know what Stephen King is reading and saying about books? Do you know that he read Red Moon by Benjamin Percy and his comment was "Finished RED MOON, by Benjamin Percy. A werewolf epic. Can't stop thinking about it."? Here you go:
http://www.bookvibe.com/people/stephenking?scope=user
3. If you want to see what books are trending on Twitter, you can browse and subscribe weekly trending books for different categories. Some starters:
Bookvibe
helps you as an author too - you can easily keep track of tweets about your book and get conversations about your book in one daily or weekly email.
http://alerts.bookvibe.com/
I'll be glad to receive any feedback to help improve our service to readers and authors.
Note of clarification: All the services listed above ARE FREE.