I've also used Tor to debug firewalls. It's a good way of saying "put me in a random spot on the Internet."
Outside of that, I use Tor for whatever I can: downloading RSS feeds, instant messaging, downloading email, mostly. There's no reason not to have Tor on these things because they're all either batched or tolerant of bad latency, and it destroys a little bit of my personal information that would otherwise leak.
So please, don't treat knowledge of the onion address itself as a secret! You still have to authenticate to your service in some way.
It's much harder to find than an IP on the Internet; I've never seen brute-force attacks coming from even a standard-port ssh hidden service.
tl;dr it's possible, and you don't have to rely on crawling the web searching for .onion addresses. You can instead become a HS directory authority, and pick your place in the DHT. Eventually you'd be able to get every address that goes into the DHT.
I use it in a container, works great. https://registry.hub.docker.com/u/hsaito/torbox-hidden/
Also TOR is heavily used by shills in same sites (namely Russian ones), so it's not too uncommon to stumble upon IP that is already banned.
- Accessing BBC Liveplayer as if I'm in England (using lots of normally discouraged add-ons and defined exit-nodes)
- Bypassing paywalls (possibly still criminal?)
- Bypassing censorship (which is what it really is) on organizational wifi networks (in Canadian hospitals). The funniest block was to ginger.io, a big data smartphone data analysis play (but blocked by an over-aggressive filter for obvious reasons).
Does anyone else have some unexpected/interesting use cases?