Link from Dafydd. Interesting business offering cost per acquisition based online marketing services. Worth pursuing at the relevant time.
Simple formula to calculate statistical significance at 95% on AB / split tests. N = total clicks, D = diff between win & lose, if D² > N, it's statistically significant. Example, 14 clicks A, 22 clicks B, N=36, D=22-14=8, 8²=64>36, win. If 2D²>N, 99%.
Mobile performance testing platform from akamai based on the webpagetest.org infrastructure, free. Useful.
Create landing pages, starts from $25 a month for 1'000 unique visitors up to $500 a month for 100k uniques. They better generate conversions at those prices!
Includes the math behind the calculation, and sample PHP code to actually generate the numbers. Very cool.
A good introduction to the statistics math of split testing.