This page will gradually expand to my personal view of 3RR. For now...
note: please do not report 3RR violations on my talk page. Put them on WP:AN3. Only notify me (why me?) of repeat offenders I've previously blocked, if you really want to.
To those I've blocked, or those hoping someone else will be edit
The 3RR rule is intended to be preventative, not punitive. To this end, at least for a first offence, all you have to do is promise not to revert the article again for a while and I'll unblock you. But you'd better stick to any such promise.
Blocking under 3RR is at the discretion of admins. It isn't automatic. There are no (ahem...) rules for how long your block will be, whether you get a warning for a first offence, or not. If this seems rather arbitrary, then the answer is always: follow WP:1RR instead and don't skate close to the edge!
There is no free pass for using the edit comment "rv vandalism". WP:VAND tends to get very strictly interpreted for 3RR: adding gibberish; blatant removal of large sections of the article; whatever. But someone removing your pet link is probably not covered. People often assert that they are reverting "obvious vandalism" when they are removing (or restoring) blocks of text; or tags. My personal test for this is that something is obvious vandalism if someone with no knowledge of the dispute can tell its vandalism easily. So adding "squerggleboogle" is patent vandalism; adding or removing an NPOV tag isn't (under almost all circumstances). It also rather cunningly means that if I didn't recognise a particular edit as vandalism, then it wasn't patent vandalism, so reverting it wasn't outside 3RR.
There is no free pass for adding (or removing) dispute tags. These are text, not quite like any other, but for purposes of 3RR they are just text.
What to do instead? edit
Being blocked for 3RR is frustrating, particularly if you're in the right. I should know. But what do you do instead? Well, in the first instance, just wait. Is this thing really so very important in the great scheme of things? Think of all the other articles on wiki just waiting for your help... OK, I knew that wouldn't work. Hey ho. Then, go to the talk page and try to discuss these changes. *Don't* rabbit on at endless length, try and set out your arguments so someone casually coming in can work out whats at issue. Find some other editors who might be interested. If all else fails, there is Wikipedia:Resolving_disputes
To other admins edit
I don't own my 3RR blocks... sometimes I write "feel free to review" on Wikipedia:Administrators' noticeboard/3RR and I mean it. If in your judgement they should be increased or removed, then do it. Of course I'll appreciate it if you drop me a note to say you've done so, at least in part to allow me to learn from my mistakes.