"The United web site runs off the same software showing availability by fare class when in expert mode. I seem to recall they have some type of interest in ITN, so hopefully both the ITN and UA web sites will be around for a while."

Even though UA and ITN uses the same software, I found that the ITN web site sometimes shows discounted seat availability (i.e. "W" fares) that the UA web site does not. Thus, I used ITN a few times and have been pleased with their service.