My posters get a bit creased on the corners (except for the heavily laminated ones) and they all have tape/whatever on the back, lol. As long as it doesn't ruin the poster, it doesn't matter to me. I like to think of my posters as "well-loved"
If you're using rubber/rubber-like poster tack that can be molded like a soft eraser, it shouldn't do any damage to the poster. Framing it can look really nice though.
But maybe you've already done that by now.