[DrScump]

It would be easiest to do so for 10 million of the poorest. Microlending and clean water initiatives like Living Water give a lot of bang for the buck, both in providing water for small-scale agriculture and saving the immense amount of time and effort it takes just to haul water for drinking and household use, often poor quality water at that.

[bigquestion]

Yes its probably simpler for the poorest 10 million. For the urban poor(no agriculture) maybe some sort of 'become a microentrepreneur' movement would be more relevant? Maybe a Mechanical Turk for real-world tasks instead of computing tasks?