Add extrainfo lines for Hidden Service usage stats?
I wonder if it would be a good idea to have usage statistics of the Hidden Services network.
This could happen in two ways: a) Tor relays could send a line in their extrainfo descriptor saying how many bytes of rendezvous connections they have pushed. This would give us an idea of the bandwidth usage of Hidden Services. b) HSDirs and Introduction Points could send statistics about how many HS descriptors they have sent, or how many intro requests they have performed.
I think a) is easy to implement and probably privacy-preserving too (since RPs are picked randomly by the client out of the set of all Tor relays). Would also give us an idea on how much HSes are used. However, we should think scenarios where revealing usage stats of an RP might compromise the anonymity of the HS or its clients.
The b) idea is probably too leaky to be worth it. Since IPs and HSDirs correspond to specific Hidden Services and leaking info about them might hurt the privacy of the HS.
I'm still not sure if this is worth it, but it would be good to consider.