@rein: They use them for more than just basic word processing so I think they're pretty powerful computers. Maybe they can't do 3D rendering of a heart in real time, but even 80s computers could send emails and log on to BBS.
What makes us think that it Isn't normal to use those technologies for communication?
The fact that they've never been shown to use it and I've seen villages needing immediate help from others and their actions suggest that they think a bird is a faster way to do this than calling someone or some other form of electronic communication.
As far as security, I mean this stuff was secure enough for countries back in the 1930s and 40s where the technology was far less than what ninja villages have been shown to possess. Plus, you'd think a ninja village would find a way to have secure lines of electronic communication. It's not like it's impossible to do.
Years after "leaving" the show he helped create, Darabont wants his cut.