This has something to do with Six Strikes
There's no coincidence that this happened the same month that the Six Strikes agreement, a deal between the RIAA & MPAA and every major ISP in the USA, was to go into effect.
Recently, Comcast had a "denial of service virus" affect them for a couple of days as well. Big surprise.
For those who don't know, Six Strikes is an anti-P2P measure wherein the ISPs use a third party tracking company to spy on your traffic. Specifically, the third party connects to a Torrent and logs all IP addresses it finds seeding, and reports them to their respective ISP. The ISP warns, then throttles, then disconnects the user as the "strikes" are crossed. There was recent controversy when it was revealed that servers would be upgraded as a part of this to track business traffic and essentially put an end to "Open Wifi".
The workaround would be to use a proxy or a VPN to hide your IP address. This would make you invisible to the third party company. Interestingly, I am a U-Verse customer whose internet is "out" due to the "outage" right now, but I'm connected as long as I use a VPN. Anything blaming the DHCP services is a lie. It's the DNS that is being affected, which is what would resolve your IP for those third party companies. Using a DNS server other than an AT&T unit seems to bypass the issue...just as it would bypass the tracking.