Well, define "stupid". People *should* be able to assume that the only people reading those posts are the people they authorise, plus possibly the system admins and law enforcement bearing a valid court order.
Law enforcement accessing the data without a warrent and then deciding to sell/give it to whomever they feel like should not be a thing given that it's illegal under even existing laws supposedly controlling GCHQ. It shall be interesting to see how this plays out.
That being said, personally I assume that everything online (including encryption) is compromised or compromisable by GCHQ/NSA and that anything posted or communicated online is probably read by them. I'm confident that the contents of my internal business network is safe from prying, but not utterly certain given the extreme resources that can be brought to bear on suppliers making security assumptions invalid. (ie, that certs won't be forged by high level suppliers, tokens ID's are secure and that out of band auth via phone will mean the end users phone rings etc)
Biting the hand that feeds IT
