What is a film aggregator?

Excuse me, could you please elaborate on the concept of a film aggregator? I'm a bit confused about its role and function in the film industry. Specifically, how does a film aggregator work? What services does it provide? And are there any popular examples of film aggregators that I might be familiar with? I'm really interested in understanding the mechanics behind this process and how it impacts the distribution and consumption of films. Thank you in advance for your explanation.