When I was little and I wanted to talk with my brother, I would yell for him (Sorry, Mom). To cut back on the noise, my parents eventually installed an intercom system (we lived in a big three-story house) so we could stop yelling for each other and start buzzing each other instead. That lasted about a week, and then we went back to standing at the bottom of the stairs yelling each other's names.
So, I am not really that surprised that families are turning to technology to talk with each other in the same house. Does it seem a little silly to send a text message to someone upstairs to let them know that dinner is ready? Maybe. But, maybe it is better than yelling. Children have a hard time using their inside voices as it is.
I'll admit to sending my husband a text when I was upstairs and he was in the garage, but I think I may draw the line at talking to him via video.