Onename offers identity passcards to browse the web and receive bitcoin. Bitcoin can be sent to users who've displayed the passcard on Twitter, embedded it in a blog or on a linked it in an email signature. Users can share contact info privately, use stealth addresses for private payments. Search for & register users with the API.
Onename invites users to obtain a personal page with the goal to share private contact information either for private chat or private payments. Sign up for an API account to start integration. It requires App ID and Shared Secret to authenticate.