Sounds a bit counter-intuitive, but i think visible tattoos (arms, neck) have worked in my favor as i got older, exactly because they help in the perception that i am younger or "hipper" than i actually am. I certainly wouldn't advise anyone to go out and get one if they weren't interested in it anyways, but i think in the tech industry it's no hindrance to getting work as a line manager or IC.
Attitudes towards tattoos have changed a lot, perhaps especially in tech. Go back a while and visible tattoos (and, indeed, probably tattoos at all) were a pretty clear indicator that you weren't a "white collar" worker or destined to be one at least in the US.
