This is a treasure trove folks. Twenty free ebooks on social media and how to use this new form of community building and sharing for marketing purposes. From search engine optimization (SEO), podcasting to all the way viral marketing. You will find every thing here. It will take you a solid weekend to read through all these books.
Here is author's introduction "It’s interesting what you can find when you look around a bit on Google. I thought I’d look for a few new ebooks to read. I found 20 different ones that might be interesting to you. It never hurts to get a few different perspectives. In all cases, the first link is to a PDF file, the second link is to the site where it’s hosted."