1) The Internet's Own Boy: The Story of Aaron Swartz
Aaron Swartz was a programming genius who is responsible for things like RSS and Reddit. He was also an activist that wanted all kinds of information to be readily available to anyone, and sadly, some trouble he got into lead to him taking his own life when he was 26. This is a fascinating doc, and in true Aaron fashion, the whole thing is on Youtube.
2) Me and You and Everyone We Know
There's a lot of interweaving stories in film, but one of the biggest involves two brothers in an internet chat room, with the youngest one striking up a relationship with someone on the other side of his screen, even though he's far too young to even comprehend the things he's typing.
Another documentary, this is a hot mess of fucked up. So much so that it ended up being a Lifetime TV movie by the same name. (I can't speak to that, but the doc is fascinating) It involves an internet love triangle that leaves one party death and another in prison.