The Future of Us by Jay Asher and Carolyn Mackler

This book has a great premise. It is 1996 and two teenagers, Emma and Josh, log on to the internet via AOL for the first time. There they discover their own Facebook pages from 15 years in the future. Josh likes what he sees (he's married to the hottest girl in school, living in a big house, and the father of twins) but Emma, whose future self is caught up in a bad marriage, isn't so happy. They both decide to play around with the present to see how it affects the future, and even little changes turn out to cause big ripples in future events. The underlying tension of the book is that, while Josh and Emma are best friends, Josh wants to be more than friends and Emma is busy dating other people. I would classify it as a fun romantic comedy and an entertaining read. I think it could have had more depth to it or more reflection on how bizarre social networks might seem to a pre-internet person. It's not too racy but I would recommend it for 8th grade on up.