Download and Usage Statistics
There are two ways people can download RequestPolicy: either from this website or from addons.mozilla.org (AMO). We don't look much at the numbers related to downloads from our own website. In the long run, we don't expect that to be the primary download method that people use.
What we have done, though, is made public our the statistics dashboard at AMO.
You can also take a look at the download count at addons.songbirdnest.com to see how many times Songbird users have downloaded RequestPolicy..