Most Americans have grown comfortable giving online. But how do they know which Web site to use?

Lucy Bernholz, writing on Philanthropy 2173, suggests that it might be time for online marketplaces — such as GlobalGiving, DonorsChoose, Network for Good, and Kiva, among many others — to create a one-stop directory for such sites.

She writes: “Just as foundations of all kinds began organizing themselves a few decades back, it is probably time that these online marketplaces start doing the same. Why? Same reasons the foundations did – public awareness, regulatory input, joint research, shared interests in developments regarding technological/infrastructure/charitable law.”

Ms. Bernholz also notes an absence of Web sites that allow donors to contribute to the arts and the environment. She asks readers to help her out. Are there any online sites that channel donations to a broad array of arts or environmental groups?

What are your thoughts on a one-stop directory of online giving sites?