Reading marketing and the web related books is a constant fav of mine. I share with you one of the best books, I've come across, in a very long time.
Inbound Marketing - Brian Halligan, Dharmesh Shah; John Wiley & Sons, Inc.
The book is well written and concise. What I like the most about their writing, is the lack of ego. So many of these books are better at the authors "self-promotion" and/or opinions, than usable content. I like their balanced view on various social networking sites.
The book concludes with, "Tips from the Trenches for Startups." Although, this book is not just for startups. You could actually start reading the end first (like cheating on a good novel) and then the rest of the book. I found the SEO section the best of all my readings. And yes, it really is as easy as they say.
Enjoy and good luck.