Archaeologist Aaron Deter-Wolf (with Lars Krutak) has a book Ancient Ink about the history of tattooing, and a number of related books about tattooing in general in an international and historical perspective. I heard an interview with him, and he is frustrated that most of the popular "History of Tattooing" sites and essays are inaccurate, perpetuating myths. I'm not feeling a deep responsibility to mythbust about tattooing narratives, but a few things did interest me, so I will pass them along.
In archeological finds, tattoos are expressive of group or status identities, not individuality. They identified you with a clan or a particular ancestor, with a profession or military unit. The ancestor tattoos were often in places unlikely to be visible to the general public, suggesting that they had a mystical or ceremonial value rather than a demonstrative one. The meanings were negative as often as positive, marking one as a slave, defeated tribe, or criminal. That's quite different than the modern application of decoration for personal expression. However, I notice that tattoos commemorating deceased relatives are still common.
Even with improved modern archaeological techniques for detecting tattoos, there are great holes in the data, and we do not know what the practices are of the majority of ancient societies were. However, a generalisation is emerging that more mobile societies were more likely to tattoo themselves. A moments reflection reveals this makes sense. If you are in one place, you can express your values and that of your clan in buildings and other built structures such as walls or megaliths. But if you are more frequently on the move, you use your body which is portable to express your relationship to the universe, to gods, to ancestors, to tribes.
I wondered in passing whether being more mobile created interest in tattooing and piercing in our own day. Sailors enlisted to "see the world," and were notorious for tattoos, as is the military is in general. But settled modern tribes and individuals also tattoo, so I wouldn't push that too far.
Because palettes of paints have been found more frequently among the funerary goods of those cultures of known tattooing (or their predecessors and successors, figuring those would be good bets), recent investigators have had a new thought what is up with that. While body paints could be cosmetic, to look better, it is not a new idea that some of them might be ceremonial. But why paints for the dead? If they needed ceremonial body paint or piercing, then paint them. Yet now that seasonality, and different roles for different times of the year and different ceremonies have come up as possible understandings, paints could have a third meaning, as temporary identifiers of role or status. Urulu might paint over the winter, not so much to portray a wolf ceremonially, but to be a wolf, to embody a wolf for the tribe. Yet in spring he has to stop that. He becomes a brewer, a hunter, a fisherman. When they bury him, they figure he might need to become a wolf again in the afterlife, an ancestor working for the good of the tribe. And he will need the right paint for that. An interesting support for that idea is the strong tendency in many cultures to bury a person with more ceremonial goods that are not associated with death than those goods representative of everyday function (though those occur frequently as well).