The goal of the SSL Labs surveys is to measure the effective security of SSL. After some experimentation with an assessment of substantially all public SSL sites (about 1.5 million of them), we settled on a smaller list of about 200,000 SSL-enabled web sites, based on Alexa’s list of most popular sites in the world. Working with a smaller list is more manageable and allows us to conduct the surveys more often. It also allows us to conduct more thorough analysis to look for application-layer issues that may subvert SSL security. In addition, focusing on popular sites – we believe – gives us more relevant results and also excludes abandoned sites.

via Trustworthy Internet Movement – SSL Pulse.