From the U.S. Department of State Bureau of Consular Affairs Visa Services:
The congressionally mandated Diversity Immigrant Visa Program is administered on an annual basis by the Department of State and conducted under the terms of Section 203(c) of the Immigration and Nationality Act (INA). Section 131 of the Immigration Act of 1990 (Pub. L. 101-649) amended INA 203 to provide for a new class of immigrants known as "diversity immigrants" (DV immigrants). Alien petitioners for the Diversity Visa Program will no longer be permitted to submit a petition by mail. Instead, the Department will require that all petitions be submitted to it in an electronic format, using an Internet website dedicated specifically to the submission and receipt of Diversity Visa.