A click on the download button will open the website of the software developer that contains information about the application. It takes another two clicks to start the download that is available directly from the same website. There is unfortunately no direct link to the website of the software developer itself to verify the findings or to download the software from there.
Update Notifier can be configured to filter the results list. Filters include the listing of only commercial or free software as well as listings based on the type of update available. The program can also be pointed at a folder on the local computer system containing portable applications to check those for updates as well.