a neat service that A/B tests headlines for WordPress posts and helps you figure out the one that will bring the most traffic. It’s called BayesianWitch. - Feature Friday: A/B Testing Headlines On WordPress – AVC

"The original converted 7.6% better than the new variation... The leads from the long form version of the page were better in quality ... in most cases long form copy doesn't just boost your conversions, but it also increases your rankings too." Indepth and (inevitably) long analysis. Huge feedback. - How Content Length Affects Rankings and…

Great case study of how shallow A/B testing can send you in the wrong direction: "...there are a few things to watch out for. The first is statistical significance ... Another is the common mistake of assigning a goal that measures the short-term effect of a test rather than the long-term effect on your business. We made this mistake at Segment.i…