Interesting... IROPS post departure of the first flight for me have always been confirmed on the next scheduled and the call is always roughly "Because of (reason), you may miss your connection to (destination). You are still confirmed on (original flight), but you are also confirmed on (new flight) departing at (time). Please see a (Continental/United) Agent or kiosk for a boarding pass for (new flight)."

Pre-departure I've gotten a "Itinerary Change Notification" with a seemingly random alternative, but the invitation to look at other options myself.

Based on replies so far, it seems my "real human" call isn't something I should expect -- though it was appreciated. I'm also wondering if the fare (pretty sure it was B, might have been Y) helped. I'm pretty sure it helped with my standby list ranking -- there were 40+ people on the standby list [for an ERJ145] and I was a little surprised to find myself at #2 as soon as I was listed.