I needed this for a slightly unusual reason. I sometimes need to use my PC keyboard while standing up. I took to placing it on top of the monitor. It tended to slip around a bit, and was in danger of sliding off and getting broken.
This mat sorted it out perfectly. The keyboard doesn't budge at all. It is very sticky... almost too sticky :) Nah, does exactly what I wanted it to do.
By the way, here's a tip: don't try to lift things directly off the pad because it tends to pull the pad up too, instead twist them off. It works!