hype train

Noun

 * 1)  An audience or other group of people who are hyped over something; people who highly and sometimes excessively anticipates something that has been highly advertised and promoted.
 * That new film is being advertised way too much, but it's working – everyone is joining the hype train.

Usage notes
The metaphorical usage of the word "train" pertains to trains being fast-moving and carrying many people. The term is commonly preceded by "aboard" or other words that pertains to literal trains.