websites communicate with eachother?

Yes, some websites have the social skills required to play nice and share data between themselves! The communication takes place via program code called an API (application program interface) and requires that a language of commands or protocol is defined. This is so that both the sender and receiver can communicate and understand each other. A typical API implementation will allow one website to contact another one, verify its identity via a handshake (even computers shake hands) and then send or request certain information or activate functionality within a limited range of actions.

Using an API can extend your website's functionality greatly, allowing it to send and recieve SMSs, chat on Twitter, roam Facebook, check the latest currency information, do translations, etc etc etc!

what I do

I can implement the API of external websites (like Twitter, Google Maps, Facebook, etc) into yours so that its abilities become extended. By connecting to social-networking websites it becomes possible to extend your user base virally by making actions on your site appear in the News Feeds of friends (see this presentation of viral actions on Facebook). I can also build a new API and define its vocabulary so that your website and its functionality can be accessed by other websites, as you allow them.

case study - mygeni.org

Mygeni is a new content-based social networking site based on what you are interested in and which of your friends you really care about. Mygeni needs to interact with other social-networking structures and communication platforms. I included API functionality from five services:

• Email providers to allow inviting friends to your contacts.
• Facebook to allow one-click registration, inviting of Facebook friends and posting of content individually and to groups.
• Twitter to share content virally.
• SoundCloud to allow integrated music sharing.
• Youtube, Google Video and Metacafe to allow embedded video sharing.
• Google Maps for integrated maps and location translation to GPS coordinates.