Let's graph an estimate of the number of Tor Browser users

We already have graph to estimate the number of Tor clients and that's great. But with the botnet it became quite hard during summer 2013 to understand if the amount of Tor Browser users was stable or increasing.

The Tor Browser regularly hits on https://check.torproject.org/RecommendedTBBVersions to see if a new version is available. Knowing how many times this file is hit could help us figuring out trends in Tor Browser usage. It would only give us trends, and not an estimate of the number of Tor Browser users though, given the complexity of browser usage patterns.

I think the day and the user agent are enough information. With Apache, that can be kept by adding to the main configuration:

LogFormat "%{%Y-%m-%d}t %{User-Agent}i" tbbversions

And then to the check.tpo VirtualHost:

        SetEnvIf Request_URI ^/RecommendedTBBVersions$ tbbversions
        CustomLog ${APACHE_LOG_DIR}/tbbversions.log tbbversions env=tbbversions