Readers write in about charity, wealth, taxes, and the housing crisis.
Charity donations pledged by the world's wealthiest are picking up as The Giving Pledge attracts new billionaires. So far, 57 have joined the Gates-Buffett effort.
Bill Gates and Warren Buffett have secured $125 billion from 40 families and individuals on the Forbes 400 list of the wealthiest Americans for the Giving Pledge campaign.
Billionaires Bill Gates and Warren Buffett want other American billionaires to give at least half their wealth to charity.
Nearly half of students at four-year colleges don't finish after six years, a report finds.