Here's the problem: there is far more of a shortage of smart people than of money in medical research. That's okay though, because while $3bn sounds like a lot, it's actually a really tiny amount. I couldn't find the most recent figures, but in 2003 the US alone spent $94.3bn on medical research. That's around $123bn, adjusting for inflation. Even if Zuckerberg spent all of the pledged money in one year, he'd only be promising to increase this amount by just under 2.5%, for a single year. Can you think of a single large project where a 2.5% increase in funding for one year has made a large difference, ever? It sounds like he's actually spending the money over 10 years though, so that's a 0.25% increase in funding. I'm being generous there and only counting the US budget. The EU spends a similar amount, Russia and China both spend a lot, so in total it amounts to well under a 0.1% increase in funding for medical research over 10 years. How much more productive would you be if I offered to pay you 0.1% more over the next 10 years?