Although instant messaging is an incredibly useful tool for business communications, one of the impediments to its growth has been the inability for users on different IM platforms to communicate with one another. The problem is akin to that of the telephone in the early days, in which you had to make sure you were calling someone on the right telephone network, since competing networks did not interoperate.Although standards-based interoperability is not yet the norm in the IM world, federation can resolve the interoperability problem by allowing users of competing IM platforms to communicate with one another. A major step forward came last week as IBM\/Lotus announced that Lotus Sametime 7.5 would now be part of AOL's federated network. Lotus joins other AOL federation partners including Microsoft, Jabber, Antepo, Communicator, Omnipod (now owned by MessageLabs), Parlano, Reuters, Pivot Solutions and Thomson Financial. AOL claims that with the interoperability with Sametime, AOL's IM services will now be accessible to more than 75% of all IM users in the enterprise.The Lotus\/AOL announcement is important for a couple of reasons. First, in our semi-annual tracking survey of IM use in the workplace, we consistently find that Sametime is the leading choice among organizations that have established a corporate IM standard, and we also find that AOL Instant Messenger is the leading IM client in the workplace. The interoperability of these two market-leading systems will allow millions of IM users in the workplace to work more effectively with one another. Second, the fact that users of so many enterprise-grade IM systems can now communicate with one another will likely accelerate the use of IM in the workplace over the next two years.Do you use either consumer or enterprise IM? If so, I'd like to hear how you use it and what you think of the Lotus\/AOL announcement. Please drop me a line at mailto:michael@ostermanresearch.