To paraphrase Vizzini, one of the villains from the Princess Bride, most people think twice about going against the Open Sicilian (as White) when death is on the line. This is true in the ranks of amateurs and when playing games in blitz or online; often, this will leave Black facing various Anti-Sicilian setups, such as the Rossolimo and Moscow variations, the Alapin Siclian, the Closed Sicilian, the Grand Prix, and a variety of gambits (Morra, Wing).
Fortunately, there are a number of ways Black can successfully combat these openings, and usually can chose a setup that is similar to their favorite line in the Open Sicilian (Dragon players can fianchetto, Taimanov players can play ..e6 and ..d5, etc). Players who employ the Sveshnikov variation (A group of which I am an occasional member) are often at a loss to achieve similar play versus the Anti-Sicilians as they do when playing the Open Sicilian.
