In 2000, he led the Drop the Debt campaign, which sought to forgive billions of dollars in Third World debt, in the spirit of biblical Jubilee.
In 2002, he founded the humanitarian organization, Debt, AIDS and Trade in Africa (DATA).
He has been recruiting American politicians and church leaders to join the fight against AIDS in Africa (President Bush has committed $2 billion to the cause and congress is considering a five-year, $15 billion global AIDS initiative... is this a direct result of his actions... hard to say... is he a big part of the growing awareness of these issues that have lead to change... I'd say yes)
The way I look at it is Bono is a good diplomat and statesman for many causes (causes that aren't always the most popular causes of the day -- let's have a raise of hands for those here who know that much about debt relief or give a damn). He has the power (of celebrity) that allows him to reach the ears of those in political power. To me, this is using his power wisely and effectively.
It is articles like this one in Time that convinced me there is more than meets the eye with Bono...
http://www.time.com/time/covers/1101020304/story.html