First off, I'm totally not into completing achievements myself. I do not consider them interesting.
But lots and lots of online players do - and most computer games nowadays cater to this very human instinct of achieving something for the sole sake of achieving something. Games usually come with achievements. Some players are compulsive achievement completionists, as I learned in TWO, to my own bemused amazement. For many, achievements are a way to increase re-playability and offer something worthwile to shoot for. Same with trophies: A cluster of a few pixels forming a gilded salad bowl goes a long way to entrance players.
(The achievement of earning 10 trophies probably will be the most coveted one).
So: Question: Will PG include achievements?
Aditional questions to the community at large: Do you want achievements? Which ones?