Films (many times used intercheangably with the term movies) by popular definition are feature length — an hour or longer – pieces which can be watched in a theatre or at home on DVD, Blu-ray or some other format for enjoyment and/or educational purposes; however, shorts — or films under an hour — while not as popular amongst the general public should also be included under the header "films." Technically speaking, however, films are strips of pictures that run in front of light in order to give the impression of moving images to tell a story.
The term "films" tends to be a popular one on the internet, showing up alongside the term "review" or "movie review" as reviewing films (or movies) is a very popular pastime within the blogosphere. Most people have an opinion about the movies they watch, and consequently it is natural that people would write about it on their blogs. However, "films," might also show up as a tag for blog posts about the physical film used to make some movies or for film development techniques.
The term "film" may be more popular than "movie" because it tends to have a more academic connotation. The term also shows up quite frequently in conjunction with foreign and independent movies. Literally, however, movie is not intercheangable with film as "movie" doesn't require any sort of actual physical film to be used.