When you have a broadband connection there is a connection path between you and the Internet Service Provider. This connection path that carries data is referred to as contention. Many users will be using the same connection so when service providers quote a contention ratio of say 50:1 this means 50 other users will be using the same connection as you. This could affect you at peak usage times as the connection could become congested. Normally however you can expect this not to have a significant impact on your connection and broadband speed.