Do you have purchased applications in the last several months or even years ago and have today no idea what the serial number was?
Do you have to dig the registration info for a software, which you had purchased last year, in you email archive? Are you searching for the invoice or license file for a registered software?
Or do you just want to bundle all the "stuff" related to the software which you have purchased from an online store?
Appshelf is exactly what you need