All too often, the recruits for these mass movements are those with the time to devote to them - not necessarily those qualified (in any sense of the word) to contribute.
Finally the leaders of these mass movements become rockstars - and from there either they are corrupted by their power, or become victims of their own fallibility, because no one is smart enough to be a god... unless they go completely offstage (or worse, die) before they make their first mistakes.
This is why Anna Hazare's "anti-corruption movement" in India is at best a quixotic piece, and at worst a circus that is going to benefit media TRPs more than the country. I almost feel sorry for the man - he has one good idea, but no vision to speak of, and is now cornered by his own followers. He reminds me of Raju Guide more than Mahatma Gandhi at this point!