Meebo released their Firefox extension earlier this morning. It lets you chat with people on six different popular chat clients, or sign in to all at once with your Meebo ID using a sidebar in your browser. The 64k extension is aimed at solving the problem of providing active notifications for friends and conversation activity--one of the most widely requested features from Meebo users, and the hardest to implement without something that has deeper access of your browser. If you've ever used Meebo before and been annoyed you can't tell a whole lot about what's going on when it's not your main tab or when minimized this extension solves that with colored taskbar pop-ups. And as an added bonus for the lazy, there's an option to automatically sign into the service every time you start your browser.
Once installed, the buddy list can be hidden and summoned with a shortcut button that sits next to your home button. You'll also get a brief overview of what a buddy has written right in your sidebar, and a numbering of missed messages both in the bottom corner of your browser, and by their username.
Any conversations take place in a special browser window that's tied to the side bar. The one caveat of using the service is that this tab needs to be open at all times, and that conversations take place there until you pop them out. Closing it out will simply sign you out. According to Meebo's "marketing dude" Daniel Bernstein, there are no plans to get rid of that open tab. Considering Meebo's monetization strategy relies on the advertising and content partnerships that you'll find in the Meebo home screen, the company isn't trying to replace the need to see that screen with the extension.
As an added bonus for Meebo users who feel like sharing content they find around the Web, the extension lets you drag over links, or entire chunks of text from other windows. It's similar to Meebo rooms, although lacking the neat video drag that will open up the Flash video right in the IM. Also, speaking of rooms, you're not going to be able to access them from the sidebar--that functionality remains a part of Meebo.com.