The G-20 wasn't only about iPods and Michelle Obama's wardrobe:

Credit where credit (line) is due: the G20 outcome was better than I expected, with something substantive and important emerging — namely, much bigger funding for international financial institutions (IFIs), plus expanded trade credit. This will help smaller, currency-crisis countries a lot.

A turning point? No. But realistically, most big-time international meetings produce nothing; this did something significant.