I don't know if it was home video. Mobile phones (texting, taking pics, yes, even taking calls) are all things I've experienced in a theater. It might be the fact that we all carry decides capable of distracting us and everyone around us - and many feel perfectly entitled to do what they want when they want.

I blame iPod - it appears that a lot of people have their hearing damaged (supposedly with prolonged listening to headphones) and talk very loudly because of this. I don't remember people yelling to each other during early 2000s movies (when home video had been already quite old but the iPod was not so popular and $200+ headphones were only for crazy audiophiles). For the past 5 or so years it's pretty bad. Especially children, who probably trained their voices to communicate with their half-deaf parents. It could be me getting older and experiencing the "get off my lawn" syndrome, however I'd imagine I should become less sensible to loud speech due to natural hearing loss with age.