I gather it's a little similar to Filehippo's UDC?
Not really. I have Filehippo, too, but it checks only for softwares new updates, not security-wise.
Fair point.
It's also, obviously limited to any database Filehippo has.
And PSI is also, obviously, limited to any database Secunia has.
I gave PSI a whirl, it showed three out of date programs . . . two versions of Flash 6 (one from Dreamweaver MX that isn't installed, and one from my other boot, where I don't need to update it) and another - an out of date version of MDAC, also from my other boot.
I found it very slow to launch, and also inconvenient to use (no shortcuts were installed).
I may try again when it's been developed more, but for now it's disappearing from my PC, like Bigfix.