82 karma · joined August 3, 2009
I was planning on allowing providers to pull achievement data back out like you're suggesting (unless I misunderstood you) but I'd also like to have a centralized listing of achievements as well. It allows users to discover sites/service that their friends are using, which would drive new targeted traffic to those providers. I think users would be more willing to check out sites/services if they see that they're friends are using it. If a user is already using a particular service and sees that a friend of theirs just got an achievement, their natural urge to be competitive could drive them to check it out and get the achievement themselves.
It could also be useful for helping users decide things in marginal situations. Imagine a user is hungry but not yet motivated enough to do anything about it - seeing an achievement from a friend where they got 10 points for ordering a pizza online could help push that user in the direction of completing that achievement, and in doing so driving revenue for that provider.