For what I see, privat tabs with Tor don’t count to rewards.
So, it would be great if private tabs using Tor would be counted as usage of torproject.org, so users could directly contribute to the Tor project this way.
Maybe some contribution “throttling” (i.e. max. 5% of my monthly contribution should go to one site) of usage should be implemented as well, so that Tor power users won’t have a too high Tor/Everything-else ratio.
Surely, torproject.org has to register itself as publisher for this as well)