Finally there came some good news related to the chat of Facebook. It is announced that the chat is using XMPP protocol and thus is usable via any standalone client as opposite of the one integrated in their web site.
Someone else has made some findings related to this, saving others the trouble.
Now ahead with developing sites using XIFF to interact with Facebook contacts.
Facebook Chat supports the following features of which most are available in the XIFF trunk version:
- Password authentication (DIGEST-MD5)
- Receiving roster, including updates
- Receiving presence
- Receiving vCards (XEP-0054)
- Sending and receiving plain-text messages
- Sending and receiving typing notifications (XEP-0085, *not* XEP-0022)
- Setting yourself idle using a show element in presence stanzas
As a final word, it is worth of mentioning that the crucial part of identifying a user is not yet supported in XIFF. That would be Digest-MD5 authentication method.