I've used it in a boat-building workshop, but I'm not clear on what "doorskin" is. Is it just plywood made of a single ply? What is its intended purpose? Is it sold at building supply stores that have plywood?
The one suggestion I've seen for DIY house work is to use it when building a ripping guide for a circular saw. You attach a reliable straightedge (like a factory-edged strip of plywood) to a piece of doorskin, then cut the doorskin with a saw. The reason for using doorskin is that you don't lose much of the cutting depth of the saw blade.
I tried Google, Wikipedia, homedepot.com, and lowes.com, and couldn't find it. Maybe my google-fu is weak today.