So does this imply that there are no software upgrades (including security upgrades) if I install something not in my repositories?
Having checked: Clicking the "Install" button for the "RAR" app redirects to "apt:rar?section=multiverse", which, I imagine (not having Linux installed, I can't follow further) opens in Synaptic. Looking around, I can't find a link that doesn't point to either the default, universe, or multiverse repo, so I assume it just doesn't offer externals.
The homepage is not so updated, it does not mention the last Ubuntu version.
I don't see who that site can be useful to.
If the above is already done, a country specific repository list would be even better.
This just seems like a web-based version of the software center, which isn't a bad thing but I don't really see myself using it.
The software on this website is, to so extend, in repositories NOT installt in Ubuntu by DEFAULT.
I hope this is clearer.
2. You don't need the repositories installed to see the software, but it is nothing you couldn't achieve with other tools.