The green card lottery was established by the Immigration Act of 1990, giving foreigners in certain places the ability to apply directly for permanent residency. It is only available to people that are from a country that has sent less than 50,000 immigrants to the United States within the last five years. There are 55,000 total immigrant visas available every year and 5,000 of those are specifically dedicated to the NACARA program (Nicaraguan Adjustment and Central American Relief Act). The countries that have recently sent the fewest amount of immigrants will be eligible to receive the most visas and none of them can get over 3,500 (7% of the total).
Application to the green card lottery is considered an expression of interest in immigrating. This can be taken into account if and when any of the applicants decide to seek a non-immigrant visa at another time. Although it will not keep that from being granted, it is important to consult an experienced immigration lawyer on the benefits and drawbacks of applying for the lottery.
Juan C. Perez has a lot of experience working with immigration and applications to the green card lottery. Call or contact him online if you have any questions about the process.