In the late 1990s, several child sponsorship organizations amended their disclosures after a series of articles in The Chicago Tribune revealed that while they were soliciting money to sponsor a specific needy child, that child was not necessarily receiving the money directly.

More recently, charities that ask donors for money to buy a farm animal have added disclaimers to their pitches, stating that money might not buy a cow or a duck but finance broader programs.

Image Premal Shah, left, the president of Kiva, and David Roodman, a research fellow at the Center for Global Development. Credit... Left, Daniel Lemin; right, Heather Haines

Now Kiva is the latest nonprofit group to have to overhaul its explanation of how it works. Where its home page once promised, “Kiva lets you lend to a specific entrepreneur, empowering them to lift themselves out of poverty,” it now simply states, after Mr. Roodman’s post: “Kiva connects people through lending to alleviate poverty.”

Kiva is not the only site with transparency problems. GlobalGiving, whose Web site allows donors to choose among various projects to support, has raised money for philanthropic projects of three or four profit-making companies, according to Dennis Whittle, its co-founder and chief executive. It did not, however, tell donors that their money would support a company’s philanthropic projects rather than one proposed by a nonprofit.

For instance, it raised $975 for SunNight Solar Enterprises, a small start-up that develops solar-powered consumer products, so it could distribute 500 free solar-powered lights to refugees in camps. After The New York Times raised questions about the issue, Mr. Whittle said in a blog post on The Huffington Post that GlobalGiving was considering whether to tell potential donors when it was raising money for a business rather than a nonprofit.

Premal Shah, Kiva’s president, said he could foresee a day when Kiva really did provide person-to-person connection, once some legal hurdles are cleared and when people in the developing world began using their mobile phones to use credit and make payments.