Beginning in March, two million addresses ending with attbi.com will have to switch to addresses ending with comcast.net. In addition to this suffix change, any AT&T subscriber whose username matches that of a Comcast user will be required to change it, too (see the Associated Press article online at http://www.centredaily.com/mld/centredaily/news/local/4661887.htm).
This time, AT&T's merger with Comcast is behind the disruption to cable modem subscribers, who must now notify numerous friends, family, and clients of their change of address and reprint business cards and stationery accordingly.
To help ease the transition, Comcast is promising to provide a temporary email forwarding service for AT&T customers to give them—and their correspondents—time to adjust.