Today is a great day to buy DRM-free ebooks on O'Reilly's website from a great range of publishers (not just O'Reilly) at 50% off or more. This includes two of my books: "Migrating Applications to IPv6" and "Seven Deadliest Unified Communications Attacks". More info at:

http://migratingappstoipv6.com/2013/12/cyber-monday-50-or-more-off-migrating-apps-to-ipv6/

http://www.7ducattacks.com/2013/12/cyber-monday-deal-50-off-ebook-of-seven-deadliest-uc-attacks.html