I remember the early days of instant messaging (or IM), when a few of us quietly downloaded the program at work and used it primarily to gossip and share in-jokes. We had the distinct feeling we were getting away with something.

But at my next career stop things were different: While its social uses still enticed, IM had also become an invaluable productivity tool.

This shift in the way people think about IM is crystallized by the Instant Messaging Planet Conference and Expo, held yesterday and today in San Jose, Calif. Guest speakers came from big-timers including Yahoo! (NASDAQ:YHOO), Microsoft (NASDAQ:MSFT), AOL parentTime Warner (NYSE:TWX), and Sun Microsystems (NASDAQ:SUNW). Panels discussed such none-too-fun topics as "Legal and Regulatory Issues" and "Practical Implementation Guide."

The message is clear: The novelty is gone, and now it's time to get down to business. Hammering home this point, the conference website intones that the expo "is geared for the executive, enterprise developer, product/brand manager, human resources manager, security and compliance officer."

"Interoperability" has returned as a major concern for IM users. It's a major issue for the corporate and government organizations now seriously considering paying for something they could just as well get for free -- albeit, without security measures that are no doubt important in many cases.

Go back a few years and the main interoperability concern was from a user's perspective -- essentially, AOL IM users were irked that they couldn't talk to Yahoo! Messenger users, and so on. Microsoft at one time bullied its way into AOL's system but was rebuffed. Efforts to create an "open standard" never really seemed to go anywhere, though it's possible to create the illusion of one with overlays such as Cerulean Studios' Trillian (a favorite among my friends).

Now, however, the focus has changed. The companies considering instant messaging "solutions" want security, but also understand that sometimes productivity involves contact with people outside the organization. (Some government and other groups will no doubt require completely closed systems.) We saw this recently with AOL and Reuters (NASDAQ:RTRSY) -- their deal will allow users of Reuters' messaging system to communicate with AOL IM users.

But the mythical open standard seems doomed to remain just that -- mythical. IM companies and their clients appear willing to open up their systems, but only so far, and on their own terms.

Dave Marino-Nachison is probably on IM right now, but he doesn't own shares of any of the companies mentioned in this story. He can be reached at dmarnach@fool.com.