Lord, tell me a good standalone set of messaging between users of the website. Can paid, service. It has to be system of exchange instant messages, similar to email, with the possibility of sending to multiple users with storage of history, attended a beautiful interface "escalope" was the ability to integrate with external "address book" and user base.
Independent search of positive results has not given any plugins for well known CMS, or ancient (for example pmsys 2003), or the "chat with support", and this is not what you need.
Language — any Platform — any, but *nix is preferable
Thanks in advance.
PS.: at the moment, consider the possibility of organizing a message exchange internal mail server and a web interface to email, but there is still too much work with a file will have, and I'll be ready :")
