According to the Internal Revenue Service a donor advised fund is a separately identified fund or account that is maintained and operated by a public charity, such as a community foundation. Each account is composed of contributions made by individual donors. Once the donor makes the contribution, the organization has legal control over it. However, the donor, or the donor's representative, retains advisory privileges with respect to the distribution of funds to qualified charities and the investment of assets in the account.
A brief article about their use and popularity appeared in Forbes.