It's like MSN Messenger or AOL, except that the identities of people on it are guaranteed, and things said on it are effectively contracts. Reuters operate a similar system. There are others too but no-one uses them.
The financial world does not rely on iron-clad cryptographic security. It relies on a very well developed system of layers of trust.
http://www.reuters.com/article/us-oil-traders-yahoo-idUSKCN1...