This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Well, let's ask the most obvious question: is it spam? In other words, what is the subject line, and what does the content look like? If your mail looks like spam, then obviously it's going to be filtered as such.