Behind the @Twelephone Chrome Extension. 

The Chrome extension is only required for receiving twelephone calls. Users do not need to install our Chrome Extension for placing calls. Users also do not to be registered with Twelephone or Twitter to place a call.  This allows the broadest possible audience to click on your twelephone link via tweets etc. or our CallMe widget from your website.

So what does the Chrome Extension actually do?

1. It maintains your user presence with the twelephone servers (online, offline, away, and do-not-disturb)
2. It notifies you of other twelephone users’ status changes via HTML5 Notifications
3. Most importantly, it controls the ringer popup for incoming calls. The incoming call notification window shows the avatar and twitter name of the calling party (if available) and includes Accept and Reject buttons allowing you to answer or decline an incoming call.  
4. It also maintains in-call status so that you do not get interrupted by another incoming call while you are already in a call.
5. It also provides a reminder link to your twelephone number that can be copy and pasted into tweets, emails, blogs, etc. as well as a link to return to your twelephone user page.

The Chrome Extension uses websockets for bi-directional communications between your Chrome browser and the twelephone servers. You do not need to be on the twelephone website to receive a call - only have Chrome open or minimized. 

As other browsers support WebRTC peer-connections, more browser extensions will be added to our inventory allowing twelephone to run ubiquitously across browsers thus growing the twelephone network.