I'm the author of this Mux blog post and would love to take any questions or comments, as well as suggestions for future posts. Thank you for your interest!
tried-and-true statistical methods like probability density functions
Yahoo EGADS anomaly-detection library
Numenta HTM neural-network anomaly-detection library
We ruled out HTM due to AGPL licensing concerns. It's an interesting product, but wasn't a good fit for us at this point in time. EGADS and other basic statistical methods can actually get you pretty far.