[tor-project] Recent Tor bridge user counts are potentially misleading

[David Fifield]

Thanks for your article, https://www.accessnow.org/venezuela-blocks-tor/.
I'm writing in response to this statement: "traffic on the Tor network
... increased ... even more sharply this month via Tor bridges — likely
in response to a new wave of online censorship from the Maduro
government."

I don't think the sharp increase in bridge users can be attributed to
anything happening in Venezuela. A similar pattern is observed in many
countries at the same time, not just in Venezuela. To choose a few
examples:
Chile		https://metrics.torproject.org/userstats-bridge-country.html?start=2018-04-01&end=2018-07-01&country=cl
Indonesia	https://metrics.torproject.org/userstats-bridge-country.html?start=2018-04-01&end=2018-07-01&country=id
Morocco		https://metrics.torproject.org/userstats-bridge-country.html?start=2018-04-01&end=2018-07-01&country=ma
The same trend is visible in the aggregate of all countries:
https://metrics.torproject.org/userstats-bridge-country.html?start=2018-04-01&end=2018-07-01

If you scroll down on the metrics page, you'll see that the phenomenon
has been noted, but the cause is unknown:
> 2018-04-15 to present	Doubling of bridge users over about 45 days. Relay users unaffected. 

So while a decrease in Tor users in the past few days is likely
attributable to censorship by the Venezuelan government, the increase in
bridge users in the months preceding probably has some other, more
global cause, not necessarily related to censorship.