AppTapp Installer was merely a package manager, and they did not implement any store functionality. FWIW, in Cydia's case, I didn't launch "Cydia Store" until about a year after I launched "Cydia Installer".
(AppTapp also wasn't the first package manager for the iPhone, but maybe it was the first one on-device? The one I had used involved USB and some web page I think, but I am forgetting the name.)
>A place where items may be accumulated or routinely kept.
Didn't installer.app come configured for repositories of software you could install? I seem to remember one of the first things people installed was an app that gave you extra repos to choose from