Why Apple's iChat AV won't work with Comcast anymore?

Apple's iChatAV no longer works with Comcast Service.

Up until Comcast made some changes to their service, I was so throughly enjoy Apple's IChat AV product. Ichat allowes my grandchildren to "see" and talk to their grandparents who live far away. The service now degrades so rapidly that it makes iChat unusable.

I am, by far, not the only one with this problem. This is a problem that has been documented all over the place. It is so frustrating to pay so much money monthly and not get the service I expected delivered (and many others..you will see). What is even more frustrating than the service not working, is the lack of response from Comcast-the assumed takeaway, they don't care.

To show I am not alone, here are some additional links:

http://www.iconnectdots.com/ctd/2007/...
http://www.macintouch.com/readerrepor...
http://discussions.apple.com/search.j...

Even an Apple Employee at the Apple genius bar said: "The genius mentioned that it was a known issue and that it was a Comcast problem having to do with upload speeds."

Any response from Comcast would be great. Any help from anyone would really help get my grandchildren "seeing" their grandparents again.