Many people come to Yemen for different reasons.
Most who now come are economic refugees from the Horn of Africa - Eritrea, Ethiopia, Somalia and the Sudan. They come in search of better fortunes, or they use Yemen as a stepping stone for other destinations. They remain in Yemen from a few months to a few years. The older refugees are more political in nature. The oldest are the Mujahideen who fought Communism in Afghanistan, under the American umbrella.