MacUpdate Desktop is an app that allows you to keep your software updated. It is not unlike Mac Informer, in most regards. The application has a very extensive app database, which it uses to compare the most current versions of apps against the software installed on your Mac.
When I first run the app, it listed all my Apps, Widgets, Screen Savers, Preference Panes, Plug-ins, etc. It didn't include any information about the current versions, or anything like that, which I knew it had to. So I looked into the menus and clicked on "Check for Updates". This did it. MacUpdate Desktop connected to its servers and it downloaded program descriptions for most of my apps and both the current versions and the ones I had. It highlighted in red all the Apps that were outdated. I noticed that whenever I clicked on an App, a new pane appeared that showed all the changes in the new version (or changelog). This is a nice feature.
I tested updating a few apps. I used HotSpot Shield and DropBox to test this feature. Although DropBox downloaded and installed very quickly, HotSpot Shield never even downloaded. This is not uncommon for applications like this. After all, one dead link and the functionality goes out the window.
MacUpdate Desktop is $20 per year, with a 10-day free trial.