Slot receivers line up on either side of the field, while boundary receivers are on the opposite side. In the NFL, the slot has become more prominent as players such as Tyreek Hill and Branden Cooks have proven to stretch defenses vertically. They are also effective in the catch and run game. They often run short routes on the route tree, such as slants or quick outs.

Modern slots are much more flexible than older machines. They are computer-programmed, which allows them to have many different symbols, and they are not limited by the size of their reels. In vintage mechanical slot machines, there could only be a limited number of symbols on a reel, whereas in modern computer-powered slots, there are as many as 20 symbols on each reel.

Slot machines have evolved a lot since the first machines were invented. Microprocessors allow them to assign different probabilities to different symbols. The technology of modern slots has made it possible to include more graphics, interactive elements, and even bonus rounds. In 1899, Charles Fey built the Liberty Bell machine, which is now a California Historical Landmark. By the 1950s, the game had evolved into one of the most popular forms of entertainment.

Slots are a way for airports to manage demand and keep flights moving. When aircraft have a slot to use, it is allowed to operate at specific times, which helps with runway throughput or parking space shortages. Because of this, the slots are traded and can be very valuable. One airport slot was sold for $75 million dollars in 2016 alone.