Use facebook chat without facebook account:
Now Facebook messenger is works as similar to What's app.
You get an option "Not on Facebook?" in new updated Facebook messenger. Here you can make your account with Name,Mobile Number and profile photo.
This service now available in US,CANADA,PERU,Venezuela.
Hope it will come soon to India .
How to use Facebook messenger on desktop:Social Networking Site Facebook has launched the web version of their messenger. You need to go to "Messenger.com" and login with your facebook ID.
It will open web-page with your chat history. You can use simile, and audio/video call also.