How were requests filtered?
I talked a bit about our filtering of requests as the baseline for our investigation in my last post. As one of the most-visited sites in the world, Yahoo! has had to develop techniques for identifying traffic that doesnt come from real users. For our investigation, we had the benefit of pre-filtered data based on what the Yahoo! network believes to be valid requests. For a lot of small companies, this is one of the toughest parts of analyzing traffic information. Our investigation benefited from the already-existing filters on the Yahoo! network, ensuring that we werent incorrectly counting requests as valid.