Are Microsoft and Facebook planning a tighter relationship between their instant-messaging systems? Maybe so, based on comments made by Microsoft CEO Steve Ballmer to 15-year-old Scholastic News reporter Aaron Broder. The interview, from the Consumer Electronics Show last month, was published today.

Asked by Broder about the possibility of instant-messaging consolidation, Ballmer stressed the importance of interoperability -- such as the ability for Windows Live Messenger and Yahoo Messenger users to exchange messages. Then he turned to an assistant.

"Have we said anything about Facebook?" Ballmer asked the assistant, according to the transcript. Then he turned back to Broder. "OK, we haven't said anything about Facebook," he said, laughing. "It's a good idea, Aaron; we'll see what happens."

It is possible that Ballmer was referring to the existing Windows Live Messenger application on Facebook, announced last spring. That's essentially a mini-Windows Live Messenger interface inside Facebook. For example, Live Messenger users can put the app on their Facebook pages to let their Facebook friends see if they're online in Live Messenger. Those Facebook friends can then send the Live Messenger users messages from the app, even if those friends don't use Live Messenger themselves.

However, that's not full interoperability, which Ballmer appeared to be suggesting in the interview.

For example, people in the standard Windows Live Messenger client can't currently see if their Facebook friends are online or send instant messages from that standard Live Messenger client to friends who are Facebook's built-in instant-messaging interface. Deeper Facebook integration such as that could be a boon for Live Messenger.

And Ballmer seemed to be alluding to something in the works, not something already available.

At the same time, it is possible that the Microsoft CEO just isn't up to speed on the topic. For example, according to the transcript, he suggested that Windows Live Messenger and AOL's AIM also are interoperable, which isn't the case.

My efforts to clarify the situation weren' t very successful. Asked about Ballmer's comment, a Microsoft representative cited the existing Windows Live Messenger application for Facebook but declined to comment on the possibility of deeper ties between the instant-messaging systems. I've asked Facebook to comment, as well, and I'll update this post depending on the response.

Microsoft has a minority ownership stake in Facebook, as well as an advertising partnership with the social networking site.