[acdha]

MCI retaining your phone call records for billing purposes has a legitimate use: they need to be able to justify charging you.

Where it gets controversial is retention time and reuse: ten years from now, there’s no billing justification but you might not want President Donner to demand they turn over the list of everyone who called a political rival. Similarly, you might not care if they have that data but still object to them sharing it with marketing partners (they called LL Bean, you can advertise your outdoors wear to them!) or making it available to other companies who can use it to look up your interests when you are on the phone or applying to something. This can be deeply personal: your car insurance company would definitely pay to know who calls alcohol addiction treatment numbers, an employer of a certain vein might be interested in calls to adult services, etc. Once that data is out, there’s no way to un-breach it.