What’s possible and what’s actually done are different things. It’s possible that they have every bit of discernible information available for every call, SMS, MMS, ping, web site, whatever that you’ve made. However, it’s not often sustainable to keep all of the content. It’s just too much to store cost effectively. In those cases, the transaction logs (from, to, datetime, limited other info) are probably kept for some period of time. Now, if your communication contains certain keywords – like: bomb, nuclear, agent, biological, New York City, or similar themes – then it’s possible that certain rules are in place to make special copies of those communications for later review, investigation, possible prosecution – depending on your country’s legal constraints. And that’s not counting in ECHELON and any whatever the alphabet soup of US and foreign intelligence agencies might have sniffing on the wire. — Personal privacy isn’t as well protected as we’d all like. I suggest operating under the assumption of what’s possible. But not to work up too much of a sweat about it.