In the grand scheme of everything, it wasn't really anything.
All it effectively did was suck the wind out of Romney's sails for the evening. It might threaten the post-convention bump, but those bumps are meaningless, for the most part.
It did, however, paint a fascinating portrait of your average Obama hater. They're just mad. They're not able to really articulate it that well, they're not able to really make a coherent argument as to why, and they end up contradicting themselves or getting stuff wrong. They're just angry, and funnel much of it onto Obama. A phenomenon that the GOP willfully culled for the past four years into seething, partisan id.