[apecat]

In terms of non-exit Tor relays, it doesn't. In fact, for anyone looking at your traffic, Tor relaying is opaque, unlike legal torrents.

As for exits, you'll be dealing with abuse reports from countless parties, including the off-chance that someone sends a death threat through your exit and you have may to fend off law-enforcement that still hasn't gotten the memo on Tor. In countries, like the US where any police encounter might turn deadly, I'd highly advise against running exits at home.

As a Tor exit operator, I can in fact honestly tell you not to run exits on production business networks, or basically anywhere where you're not prepared to be a recipient of a lot of unwanted attention.

[zaarn]

Even non-exit nodes can put you in a bad spot (my ISP didn't like it), you'll get blacklisted by quite a few places (because not everyone got the memo that middle nodes != exit nodes)

[apecat]

Yeah. If your ISP is manned by dipshits, they won't like Tor relays, just because.

It's also worth setting up a Tor relay to use a different external ip address. Because VPN/Procy whitelists employed by dumb web firewall products will temporarily blacklist all publically listed Tor relay IPs.

Here's a typical residential setup: ISP-provided broadband modem in bridged mode + some sensible home router with security patches you should be using anyway and the Tor relay server connected to the modem with a non-managed switch (if needed).

Please note that Bridges give help directly to individuals who can't access Tor, due to blockage in their home country. They don't use a lot of bandwidth and aren't listed publicly, so bad actors on the firewall market won't block them.

So, if you only have one IP address available and you want to do the internet at large a huge solid, just run a Bridge.

For anyone interested in running Tor relays, here's an intro to why your new box won't use all available bandwidth for a while https://blog.torproject.org/lifecycle-new-relay