A slot is a dynamic placeholder that either waits for content (passive) or calls out for it (active). It can contain any number of items, but only one type of item. Slots work in tandem with scenarios and renderers.
In a sport, a player in this position may be a quicker guy or a shifty guy who likes to play all over the field. He will usually stand off the line a few feet and give himself a chance to get his route going before getting grabbed by a defender. This is also a good spot for a big guy who wants to run hard and not get sacked or tackled.
When a player plays for real money, they should look for machines that have decent mid-size payouts and low jackpot payouts. This way, they can avoid a lot of bad luck and stay in the game longer.
Generally speaking, slot machines will be closer to the entrance of the casino or a high-traffic area in order to get more players to them. This is because higher traffic means more people playing and more chances to hit a bonus event. This is a very important point because a bonus event is what keeps most players coming back to the game, rather than just regular play. This is what the casinos are banking on when placing their machines. They want people to come back, not just to gamble. This is why they place the popular games in visible spots.