Woah. that quiet unassuming link down there actually attracted two faves to my page XD

I never knew that tattoos were such a heated topic. o.o Pretty awesome.

You're missing one additional method related to the last one (branding): Its called Scarring.
The process is where you cut the skin and intentionally agitate it during the healing process to make the scar larger.
Here's a great video telling about a tribe that EVERY male member gets scarring over their body to look like Crocodiles: http://video.nationalgeographic.com.....cscars-pp.html

Since most people wouldn't want the same branding as others, or a new form of making brands would have to be made to make it quicker and cheaper for people to get one custom made, I'd say scarring would be the most likely method of getting a "tattoo".

On the fur dyeing method, I think that would be more used as people do now like they color their hair; something many do because, like now, it's nothing permanent, is painless, but gives individuality. It's also limited in the fact that fur moves and would prevent any type of detail from being incorporable.
This would also be an issue for the first option. Imagine getting a face tattoo then your fur grow long: You'd go from Mona Lisa to
the Scream painting. :P

not so fast, fasty. :P give us some time to draw and release the next episodes.