Originally Posted by wimpypipsqueak
I'd like to know what sending a message to Inventory Management to open a seat actually does. They've offered this in numerous occassions when I've called, but a seat never seems to open up.

It's essentially a request. If the flight has plenty of open seats, and IM's historical load models show that some of those seats will not be sold, they will open them.
In the case of your others flights, if there are not many open seats, or IM's load models note that they sell most of them, they will not open one, lest they risk giving up a multi-four-figure sale.