There's a well-worn plot in which a man and a woman have a relationship, fall in love and are then forced by circumstance to part. Years go by in which they marry other people or imagine the other person is dead or whatever - in any case, they don't see each other again until one of them is on their death bed.
I've just read a novel by a famous literary novelist (who should know better, imho) that has exactly this plot. It finishes in the 1980s.
With the internet, that sort of plot will just disappear, won't it? You lose track of someone, you look them on Facebook or LinkedIn and if you feel like it you get in touch with them.
Are there any other plots you reckon will disappear thanks to the advent of the internet, mobile phones etc?