Interesting, I have been using an app for the last couple of weeks called updatenotifier (http://cleansofts.org), which does similar things except manually for the download side of the house. What they do though that I think would be extremely useful in Ketarin is a scan of the local machine for application installs. They appear to be building a database (online) of apps and have other things in mind for that facility.
This could be used as a very good starting point for the input of applications. Tie that in with the software update searches that other folks are looking at and you have an extremely powerful and useful app.
Keep up the great work!