Great article! I think it's interesting to see the different reasons why people go after achievements. For some, it's just a personal collection; for others, it's a challenege to overcome; many more people use them for bragging rights.
I've never been a collector, but the challenge and bragging rights greatly appeal to me. Unfortunately, most games miss that fact. I've played far too many games (mostly new ones that assume they have to have achievements to play with the big kids) where the achievements were little more than milestones along the typical gameplay. Really, who needs an achievement for beating the first level? I would think that beating the first level is its own reward and it's not really something to brag about. Finishing the game? That might be more of a feat worthy of bragging. Doing it in 20 minutes? Yeah, that's definitely an achievement.
I also agree that achievements mean different things between single-player and multiplayer. The Peggle-style celebrations are key to the single-player experience, because an achievement has to feel like more rewarding than just finishing a level. It's like the cutscene and music when you finally finish a game -- congratulations for a job well done. The more fanfare, the more it means.
But multiplayer, you can really go to town with it. It's not about the achievements being visible to yourself, but to everybody else. Nothing beats the feeling of having guildies (and random strangers) congratulating you on your latest achievement. Doubly so when it's a bizarre, difficult achievement and you get people asking, "How did you do that!?" That sort of social posturing truly is a reward, and it ought to be a central mechanic in a social game like any MMO.
As was mentioned, an example of achievements done poorly is the Xbox. Consider when you are playing Rock Band and you play your first big challenge to win the tour van. When you win it, that little "blip" plays and the icon comes up, but nobody gives a shit about that. My friends and I were all laughing at the broke-ass van that was now proudly displayed on the screen in front of us. I couldn't have cared less about the XBL achievement -- the real achievement was given to me, in the game, in the form of a graphic of a van and unlocking several new parts of the game. That's a reward worthy of an achievement.
