Ask HN: This whole "change the world" mantra. What recent startups qualify?

I'm hopeful for Bank Simple, Square, and others trying to fix up the way we pay each other and take payments. Having operated a small business (salon) for the past two years, merchant accounts, payments, etc are all a total black box and you have no options/control.

Mendeley I think definitely qualifies.

Lanyrd has the potential.

Very far and few in between. So, my question is "why"?

massivehealth.com is supposed to disrupt the health industry.