Enterprises are coming to terms with Instant Messaging (IM), finding that it has become the best way to accelerate new forms of collaboration and communication among their distributed workforces and stay productive as email inboxes swell with spam. For some companies, email has become the new snail mail. But before you bite the IM bullet, here are some questions to answer to formulate your potential IM strategy for your corporation.
As said in the comments of the article, you’ve missed the most important point: Jabber/XMPP is the only open internet standard, it has been standardized by the IETF, the organization that made most of the internet protocols.
Many proprietary and opensource solutions based on Jabber/XMPP are available, you can find one that will fit your needs.