I was personally using it but, even though, I was connected, I was rarely chatting. But, the main reason why I used Messenger (2009) was because how useful it was regarding e-mail notifications. If I had a new e-mail coming in, a popup would appear and if I clicked it, it would open a new tab immediately in Firefox. If I missed that notification, there was the button in upper right corner showing a (1) so I would click on it and get to my new e-mail. That's the only thing I would miss it for.