Read This Book!

The Online Advertising Playbook
Proven Strategies and Tested Tactics from The Advertising Research Foundation

I recently had to read this book to put together an online media rational and it was the best resource!
This book is very interesting, easy to read, and serves as a great resource to reference back to.

It contains:
Targeting Approaches: A Unique Element in Online Advertising
Online Advertising Reach and Frequency Concepts
Winning Strategies in Online Advertising
Display Advertising Online: What to Choose...