James was recently in Manitoba, and he tried to access this site. I presume there isn’t some anti-west coast censor in Winnipeg, so I guess my site was down or otherwise unreachable. Instead of an “Address Not Found” message or status notice from my web host, he saw this page from Manitoba Telecom Services (click for embiggenness):
First off, what kind of index or algorithm are they using to generate those categories? They’re very peculiar, and, at least in this particular case, useless to the user.
Is this sort of thing a good idea? From a user experience perspective, my answer is ‘maybe’. If MTS presented the user with, say, a set of search results for “www.darrenbarefoot.com” and pointed them to the cached version of the site, then that’s plausibly useful.
From a privacy perspective, this is not cool. I don’t want my ISP highjacking my web connection, even to be helpful. They’re a utility, and should act like one. I don’t want the City of Victoria offering me flavoured water from my taps, and I don’t want my ISP volunteering to help with my web browsing.
DarrenBarefoot.com 
Not only are these DNS interception responses unhelpful, but in certain circumstances are actively harmful.
These catch-all portals can potentially earn big dollars in advertising, and can (inadvertantly) capture usernames and passwords from systems and clients not expecting that another service might suddenly appear in the middle.
There have been more than enough examples of ISPs doing this for it to be a known issue, and something those with any brains or integrity won’t do.