My Experience:
At some point, a few days agao, I noticed that any invalid URLs I typed in weren't generating the usual error message but instead resulted in a strange looking "Shaw Assist" page with a URL of assist.shaw.ca which, when entered in to the address bar, switched to shaw.assist.ca. Somewhere on the page was also an "About This Page" button. I tried searching for those URLS and for "Shaw Assist" and "shawassist", all without luck. Being paranoid I did not click on the "About this page link".
Instead I invoked a Shaw chat session. My mistake. After describing things much as I did above, I was asked the usual irrelevant questions about settings, browser settings, security settings, etc. Even my telling the rep that the behaviours occurred on PCs and Macs using FF, IE and Safari on three different computers didn't help. I suspected that it was Shaw intercepting the 404 response but even telling rep that didn't help. Oh, I was also told that there was no such server as assist.shaw.ca.
After some time (possibly a coupleo f hours) and after two or three discussions with his/her higher-ups I was told "Oh, it's a new service from SHaw....DNS Redirection..."
Only after that was I able to find the one solitary Shaw reference to (mentioned earlier in this thread) and only then was I able to find this thread about the topic.
I can see that some might find such a service useful but for heaven's sake Shaw, please tell us about it.
Incidentally, Opting out worked for me.
Aside: Now I have to try and find when Shaw's outgoing email servers started intercepting bad outbound Shaw email addresses (maybe it's nothing new) - It drove a friend (and hence me) nuts trying to debug an error with his Outlook Express that had nothing to do with anything he was trying to do now - It had to do with Shaw's repeatedly rejecting his Outlook Express programs attempt to retransmit an earlier Shaw-blocked message. Undoubtedly another new feature. But that is for another time and place. end Aside