1. A method comprising: gathering programs watched data from a plurality of terminals; analyzing the programs watched data to determine a frequency of programs selected at the plurality of terminals; assigning a plurality of categories of advertisements to the plurality of terminals based on the analyzed programs watched data, wherein each advertisement category includes a plurality of advertisements; transmitting a switching plan to the plurality of terminals, wherein the switching plan directs a first group of the plurality of terminals to switch to a first advertisement included in a first of the plurality of categories of advertisements during a first program break and directs a second group of the plurality of terminals to switch to a second advertisement included in a second of the plurality of categories of advertisements during a second program break, the second group of the plurality of terminals including at least one terminal common to the first group of the plurality of terminals.