I operate the apx family of exit nodes. [1]
It may be valuable to know that traffic confirmation attacks [2] are seemingly taking place. [3]
[2] http://www.ohmygodel.com/publications/usersrouted-ccs13.pdf
[3] Regular 30 second windows with around 1.8 Gbit/s - 2.1 Gbit/s of traffic on each of the exits which are also guards (apx1, apx2) while the exit which isn't a guard sees stable traffic of only ~ 1 Gbit/s (apx3). Circuits to hidden services include guards and middle nodes (rendevouz point). DDoS attacks against hidden services do not affect exit nodes unless they are also guard nodes.
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