What influences do Film Posters have?

They're striking works of advertising art, but do they actually serve a purpose? Film Posters used to be everywhere, on bus stops, walls, doors etc. However recently they have been decreasing, with the amount of people now who look online, the need for them aren’t as relevant any more. Although some would disagree, posters can really influence people's decision to look further into a seeing a film, or deciding whether or not it's for you. It's also a way of giving the public an insight into the film, without giving too much away, which the web and adverts have been previously criticized for. Also not all people watch a huge amount of T.V so a poster could be their first realisation of a new film. Other's however could claim that movie posters show a film in a cheap light, which on the other side could put people off seeing a film. I personally like seeing film posters, as it excites me and makes me more aware of the new films coming out.