1. A method for mitigating denial of service attacks against and improving performance of an Internet search system, said method comprising: receiving a request for information; searching, with said request instead of a hash value based on said request, a first memory for an indication as to whether said information is in a second memory, wherein said first memory stores previous requests for information; if a result of searching said first memory is indicative of said information being in said second memory and said information is in said first memory, providing said information from said first memory; if said result of searching said first memory is indicative of said information being in said second memory and said information is not in said first memory, querying said second memory, with said request, for said information; if said result of searching said first memory is indicative of said information not being in said second memory, forgoing a query of said second memory; if on a condition that said result of searching said first memory is indicative of said request not being in said first memory: computing at least one hash value based on said request; querying with said at least one hash value a probabilistic detector, wherein said probabilistic detector is populated with at least one computed hash value based on each expression in an index of said second memory, for an indication as to whether said information is in said second memory; determining if said queried for indication is indicative of said information being in said second memory; and if said queried for indication is indicative of said information being in said second memory, querying with said request, and not with the at least one hash value based on said request, said second memory for said information.