They (for better or worse) absolutely dominate the annoying popup toolbar at the bottom of a website market.
They fixed it after a few months, but you could very obviously see that what was happening was it was inserting the newline, and then they were removing it, and then the message was getting sent. It was an obvious hack and it made me feel like they really didn't understand how to make a good iOS app, and didn't care enough to do it properly.
Meanwhile, they started adding other 'features'. They added the ability to 'check in' to a website, like foursquare for web pages. Except it only worked inside of the built-in browser in Meebo, which meant it only worked for links that your friends sent you via IM while you were on your phone. How much time did they spend implementing a feature that I can't imagine anyone ever using instead of adding actual functionality to their app (or fixing the constant crashes I got all the time)?
That was the point where I basically wrote Meebo off. Sure, they probably couldn't make money providing a free chat service, but they could have branched out in other areas, rather than the idiotic-seeming stuff they've been working on lately.
This is not something duplicated easily.
edit for links:
link for Chrome:
link for Firefox:
Ahh! Long enough ago that I totally forgot about it, I installed the Block Meebpo Toolbar userscript in NinjaKit
Full timeline: http://en.wikipedia.org/wiki/Meebo#Timeline
Now, I have no trouble understanding why you'd eventually go to gChat; it's clearly superior.