It was AT&T that was bought out, in a way.

Cingular was a brand name of SBC. Over time, SBC had gained such a bad reputation that they were looking to shed their name, much as Phillip Morris renamed themselves to Altria Group.

When the original long distance company AT&T went bankrupt a few years ago, SBC saw a golden opportunity. They bought the AT&T brand name, and completely ditched both the SBC and Cingular brands.

But today's AT&T has absolutely nothing to do with the decades-old long-distance company.

As far as I know, it was actually SBC that was involved with the spying even before they changed their name.

BTW, I lied. Cingular was actually bought out. It originally was a Pacific Bell brand. SBC did buy Pac Bell. But that was many years ago - I think it actually was last century - and I doubt that you had this merger in mind.