In todays market place more and more software vendors are moving to diskless methods of software delivery.  For software vendors, speed to market and the decreasing cost of Internet bandwidth makes this an attractive option.  Customers benefit by being able to download the latest product versions without having to rely on CD-ROM's and DVDs that are typically outdated within a few months.
IT departments should have a consistent plan in place to purchase, receive, track and deploy the licenses for downloaded software products.
If your corporate purchasing department is involved in buying electronic software products make sure your purchasing department is giving your software vendors end-user contact information.  Furthermore, use a generic email address '' when registering your software.  This way you avoid the issue of having update your contact information with multiple vendors when changes are made to your IT staff.
Download all software purchases to a shared location on your network.  Create a separate folder for each product that you download.  When needed create a 'patches' or 'Service Packs' subfolder for each product your download.  Only store purchased products in this location (do not download demo's or non-licensed software to this location).
Use Web Tracks to create a 'Software Asset' record for the purchased product.  Save all correspondence regarding the software purchase to files.  Emails can be saved to text/html.  Save web pages in an archive type format (.mht for Internet Explorer).  Finally, attach these documents to the Software Asset record in Web Tracks. 
Use a user-definable field in Web Tracks to track maintenance contract expiration dates.
Whenever you install a copy of software that has a 'per machine' type license use Web Tracks to allocate a copy of the software product to the appropriate computer.  Similarly make sure to de-allocate the product from a computer if you remove the software (disposing of a computer in Web Tracks automatically deallocates software licenses).
In conclusion, having a plan in place to place to deal with downloaded software products will make your life as a IT administrator less hectic.  By following these simple steps you might even begin to prefer the electronic method of software acquisition.