I find that lookback of 2 generally creates more entertaining titles. Lookback of 3 usually seems to just splice together two titles (which can be hilarious, and is usually more grammatically correct), and lookback of 1 tends to generate more nonsense.
Some fun ones I found just now:
The Neuroscientist Who Discovered He Was a Teenage Hacker
How my comment on TechCrunch got me a new, useful superpower?
PHP Sucks But I Didn't
Windows 8 is 20% faster than C
The Navy’s newest warship is powered by WebGL
Cards Against Humanity has made comments even worse, I'm leaving
How Porsche hacked the financial system and made a html5 game, polished it many many times
Interestingly, if I change the code to pick the most likely word, followed by the most likely word, etc. the "most probable" post is "The New York Times and The Internet"If I limit it to just 2013 posts, it is "The NSA surveillance".
My site is running on the smallest Digital Ocean droplet (512MB), if it goes down, I will feel silly. If it does, code can be found here: https://gist.github.com/grantslatton/7694811