DEADPOOL

Deadpool was a box office success for many reasons, one reason is because it wasn't aired at the normal time for big films during the summer when most people are off work. Instead it was released 12th February which is not the normal time for big movies to come out. So because it was released at this time people wanted to watch it more as they would need to make time for it.
Another reason it was popular was the way that Deadpool the character acted, most other super heroes acted politely and saved the day doing good things whereas Deadpool was more rude and the movie was gorier. People would want to watch this as its not the normal thing and people might prefer this as its more realistic.
Another reason is because of the way it is written, in many scenes of the film Deadpool talks to us the audience while the background is frozen, this give a huge connection to the audience watching and makes the think about the film and be drawn in. This isn't normal and would give the film a variety. It also allows him to explain context without confusing the viewers.
Also this film was different as most films have a beginning middle and end, whereas it was different in Deadpool as you found out the very start at the end.
They released the trailer on Christmas day where everyone would be off work or school and would be able to see it which would have drawn in a lot more people that usual. Deadpool already have a bug fan base as he is a well known comic book hero.
Choosing Ryan Reynolds as the lead actor was clever also as he was already liked by a lot of people as he was well known and would have drawn in more fans.