For a time, it was popular for movie trailers to end with a domain, often of the form "${ $TITLE }film.com", which would take you to the marketing site for that release. Nowadays there's a whole TLD specifically for movies.

It's a shame that isn't a norm for you to be able to plug a URL into a reader that consumes application-specific RSS (à la podcast clients) for the express purpose of giving notifications when that film is available (either for rent or by subscription) on a new platform.

(Ideally, of course, the media itself would be self-hosted, so you could paste the URL into e.g. VLC and encounter a platform-neutral way to negotiate payment directly with the distributor (or not and just get embedded ads—à la podcasts) and then you're off to the races.)