The difference is just in the packaging. Although software doesn’t need a box anymore, this wasn't always the case. When consumer software first became available in the 1980s, the box was necessary, since it contained a number of floppy disks with the software on them, as well as a printed instruction manual.
Today, the box is virtually empty, containing only a CD or two. That’s because everything that used to come in the box, (the program that would have been on a number of floppy disks, as well as the contents of the printed instructions manual) is now shipped as files on the CDs.
And with software being sold both on the internet and in stores, there are now 3 ways to buy software
- buy the software on the internet and then download it (Software Download)
- buy the software on the internet on CD-ROM, which the vendor will then ship to you (CD-ROM)
- buy the software in a store, in a box
No matter which way you buy your software, or how it is packaged, the contents will be the same.
You can always download a new copy of the software from the vendor, or from a Download Site.
If you’re really concerned, you might want to burn a backup copy on to a CD when you download the software.
If you've misplaced your Registration Information/Serial Number, you can usually get it replaced by emailing the vendor.
According to the Association of Shareware Professionals,
"Shareware is a method of software distribution and marketing, and not a type of program. In fact, try-before-you-buy software has been discovered by traditional "shelfware" companies, and now, nearly every large software company provides some type of free trial version of their software."
So, technically speaking, shareware is defined as software that lets you try some or all of the features before you buy it. If the software download allows you to try the software before purchase, it's shareware.
This means that today, most commercial software manufacturers are also shareware authors, since most commercial software manufacturers now allow you to download a limited demo version of the software before purchase.