Rainmaker is a service that allows users to enhance their Google Contacts by retrieving public social information about their contacts. Not only does Rainmaker enhance Google Contacts, it also allows users to manage their contacts from the Rainmaker interface; any changes made to contacts in Rainmaker will be reflected in the user's Google Contacts.
Rainmaker also has a RESTful API that developers can use to integrate Rainmaker into their own creations. The API takes an email address as a parameter and returns available public data about the address, including social profile data, in JSON or XML format.
Rainmaker is a simple and powerful identity API designed to help users get more info about the people in their contact lists. Rainmaker recently announced a developer's contest for apps built on its Rainmaker API.
“Hey Smitty, I got this guy’s email address. Can you do some digging and tell me more about ‘em? How much does he make? What are his hobbies? Oh, and I want to see pictures of his pet dog too. Can you do it?”
“Yea boss, I’ll get you your information, buckets full of it. I’ll make it rain!”
This is the imaginary old timey gangster context I imagine around the idea behind Rainmaker, its contacts service and Rainmaker API.