The company said today it has launched a browser add-on prototype named "Snowl" that displays Twitter messages, or tweets, as well as RSS or Atom feed content, in either a traditional single-window view within Firefox, or one featuring several separate panes, said Myk Melez, a senior software engineer who works in Mozilla Labs, the company's research arm.

Snowl is part of broader work at Labs to explore both near-term tools for Firefox and longer-range overhauls of the browser. In Snowl's case, Mozilla is trying to decide whether messages that normally appear in their own separate desktop client applications or via pop-up notifications, belong in the browser.

"We want to find out whether there's a role for messaging in the browser," said Melez. "Can it become a hub for messaging?"

Snowl—a compression of the words "snow" and "owl"—can be downloaded from Mozilla's add-on site. Melez, however, warned users that as a prototype, Snowl may be buggy. "The initial prototype is a primitive implementation with many bugs, and subsequent versions will include changes that break functionality and delete all your messages, making you start over from scratch," he said in a post to the Labs' blog on Wednesday.

"Extensions are a great way to prototype functionality in Firefox," Melez added in an interview today. "But I want to stress that this is a Labs experiment, and doesn't mean we're adding this in Firefox."

Instead, Snowl—as well as other ideas Mozilla publicized earlier in the week, including a dramatic conceptual rendering of a new browser design dubbed "Aurora"—is a toe-in-the-water kind of experiment.

"The reason why we're conducting this experiment [with Snowl] is because we don't know if messaging should be in the browser. But we want to find out that, and a lot of other things."

With Snowl on the street, so to speak, Melez said the next step is to collect feedback from users, developers and potential developers, then decide whether it's worthwhile to continue developing the add-on and, by extension, the concept of in-browser messaging, or just scrap the whole idea.

"We want to gather as much feedback as possible, [then] make the decision [to continue] if it seems promising and adds significant value to the browser," Melez said. "Those are the questions we need to address. But it's still a successful experiment, even if something doesn't make it into the browser."