When you send an IM on meebo and the person doesn't recieve it. A meebo fail usually follows with "meebo message: could not IM buddy" or "meebo message: could not connect to network"
B@biigurll169: hey bob
Bobbyboii86: do you wanna go out wih me?
Meebo Message: could not IM buddy
B@biigurll169: do you like lemons?
Bobbyboii86: ughh meebo fail