Originally Posted by X-Maniac
I believe that a lot of people who saw Avengers hadn't seen all of the individual movies; the film was just a big summer event.
I'd go even further and say that The Avengers managed to get the people who'd rarely bother with a superhero movie, period.
And IMO the main difference between it and DoFP is that it was basically a first film in the new series and worked as an introduction to the characters. Rather than a next installment in a 10-year-old franchise.