Its not enough publish a list like this and not add explanation, but right now this the beginning of a thought and there will be more coming.
Working for the Government
Brands (and the question of what a brand is, i.e. it’s not a logo and a Pantone color)
Email (I’d rather receive a text than get an email if only the artificial 140 character limit was discarded)
Social Networks like Facebook are in need of disruption, but will probably die first in favor of new networks.