RPS Asks: Steam Achievements?

An open question for the floor: how much stock do you put in Steam's achievements, now they've been around for a couple of years? I only ask because they're cropping up in more and more games, yet yet they don't seem to have hahahahaha achieved the same game-cultural significance as Xbox 360's ones, where folk from all walks of life seem invested to the point of violence in their Gamerscores.

Steam's don't appear to go towards a global pool of gaming accomplishment in the same way, but instead appear to only reflect upon the specific game they're from. But have they quietly managed to become of great, fervent import amongst the more dedicated PC gamers? Do you do a happy little clap when you earn one? Or are they entirely incidental to you? An annoyance, even?

They haven't really clicked for me, I must admit - when a box pops up saying I've done such and such I don't perceive it as having any impact on me, unless I'm fairly sure that it's going to lead to something new activating in-game. But they're increasingly prevalent (which I guess to some extent goes hand-in-hand with the proliferation of Steamworks), which would imply they're doing something right.

So, thoughts? Do you even know how many of 'em you've got? DO YOU KNOW WHERE YOUR CHILDREN ARE RIGHT NOW?