Smart phones allow multiple ways to connect with friends, from phone calls to Twitter messages, but each has its own app or in-box. Now the cell-phone manufacturer Nokia is experimenting with a universal in-box that puts messages and updates from separate apps in one location, so you can see everything at a glance.

The universal in-box looks superficially like a regular e-mail in-box. But the stream of recent messages can be a mixture of e-mails, text messages, call logs, tweets, Facebook updates, Flickr photos, and more.

Just last week, Facebook launched its Messages product—aka an “e-mail killer”—to combine e-mail with text messages and private Facebook messages. Smart phones can already receive messages sent over those and other communications channels, but the messages are stuck in separate app “silos.” “The universal in-box brings together all those communications into one place so the user does not need to check separate apps,” says Rafael Ballagas, a researcher at Nokia Research Center, in Palo Alto, California.

That makes it easier to track and carry out conversations that span different kinds of messaging. For example, it would be simple to see that someone responded to a Twitter update with a text message. It would also be possible to seamlessly switch methods of communication, and reply to a person’s latest Facebook update by e-mailing them.

As a result, users can think less about the medium of communication, and more about the people they are contacting and what they want to say, says Tim Sohn, another researcher on the project. That’s particularly valuable on a mobile device with a small screen, he says.

The universal in-box is made possible by cloud software running on a distant server. The software gathers up a person’s messages from a device and connects with Web services such as Facebook. Processing these messages has to be done in the cloud to avoid overtaxing the limited computing and battery resources of a cell phone.

An additional feature called Lenses tames the potentially overwhelming volume of messages in a universal in-box. Each lens creates a kind of mini-in-box specific to a certain group of people or related to a particular topic. “You can create your own lenses for different points of interest, whether that’s your high school friends or another community like your work contacts,” says Sohn.

Creating a new lens is a little complex, though. In the current design, users choose an example of a message they would want to appear in a lens, and then select which attributes of the message should define the lens. “Programming by example should be powerful, but this is still not quite right,” Ballagas acknowledges. “This idea would benefit from more exploration.”

One alternative way to combine all the communications on a phone without overwhelming a user is demonstrated by Aro, which makes an app that relies on algorithms able to recognize people, places, and things in text to organize text messages, calls, and e-mails. A survey of hundreds of mobile users revealed that they were often frustrated by the need to regularly “context switch” to check updates in multiple applications, says Dwight Krossa, Aro’s executive vice president.

But services that pull together many sources of information can be hard to build when smart phones are designed around the concept of separate, self-contained apps. “It’s a challenge to get away from the old model of application sales toward services and systems that make life better for mobile users,” says Krossa.

Nokia is in a position to build a system like its universal in-box into the operating systems of its own phones, although the current prototype is only a research project. But like Aro, it would still rely on being able to tap into other services, and could risk irking app makers concerned about missing out on ad revenue and other benefits of engaging their users directly.

Krossa says that helping users is never bad for anyone’s business, though. “We should let the users decide whether or not this is bad for the maker of the existing application.”