Ask HN: Do you use Gravatar or other services to autofill users' profiles?

I'm thinking of building something that's like Gravatar but for bios, and I'm looking to hear more from people that use third-party services to auto-fill profile information for users.

* Are there other services you use?

* How ubiquitous does a service need to be before you trust that it'll have decent hit-rates for users?

* Are there other considerations that go into your decision?