Free Social Media eBooks

Just found this now, even thought it was posted a few weeks ago: Mashable features a list of 15 free Social Media eBooks. I know some of them already, but it’s worth taking a look at that list. For some reason, it appears to me, that free ebooks are becoming ever more popular. Not so much as a true means of spreading knowledge, but rather as a marketing/pr instrument for individuals and companies. Don’t you think?