Trailers are used to introduce audiences to films by showcasing characters, themes and stories. Audiences can now access trailers through various online and social media platforms like YouTube, Facebook and Twitter, as well as on TV and in cinemas. Social media allows audiences to easily share and discuss trailers, and encourages engagement with competitions and games. The platform and rating of trailers shown depends on the intended audience of the film. For example, children's films will have trailers on kids' TV and before lower rated films. Trailer exhibition has significantly changed over time with greater online access on various devices. Trailers are regulated and rated to be compatible with their associated films while suitable for all audiences on social media.