This is what I got from comcast.
Important Speed Increase Update
Just when you thought the internet couldn't get any faster, Comcast High-Speed Internet brings it to you with more blazing speeds than ever before.
During the previous weeks Comcast has been upgrading all of our High-Speed Internet Service customers from 3Mbps downstream and 256Kbps upstream to speeds as fast as 4Mbps downstream and 384Kbps upstream - at no additional charge.
All residential Comcast High-Speed Internet markets have now been upgraded to the 4Mbps/384Kbps service.
That speed increase has nothing to do with the announcement in the above article.