@Baz I think you are referring to the link there which is to branded mobile apps - that's for administrators of sites rather than us and I think is intended for those adminisrators who want to promote their site on a commercial basis, ie they want to advertise.
I think the Gaga app you are referring to was closed as when the site went over to a "responsive" site (one which automatically adjusts depending on if you are using a computer or a tablet or a mobile phone) there was no further need for the app.
If I'm mistaken about this, Lori would know what's what.