Items placed in the public domain are free of all restrictions.
Freeware or "Copyleft"
These items are protected by copyright, but the owner has given permission for free
non-commercial distribution. You should read the copyright terms to determine if the
author has retained any distribution rights. For example, many "freeware" copyrights
require you to obtain permission before including the software in a commercial product.
These are commercial programs distributed on the "honor" system. You are permitted
to copy the program and use it for a specific time period (typically 30 days). If
you decide to keep the program, you must then pay a shareware fee to the copyright
holder. Shareware has become a popular method for small software publishers since
it bypasses conventional marketing channels.
Demoware are crippled copies of commercial software. They permit you to test out the
program, but you must purchase the software before you gain full functionality. For
example, the demoware may be identical to the full product except that it cannot print
or save documents.
Some copyrighted software includes special coding that prevents successful copying.
This can take the form of an encryption key, use of a hardware enabler or use of a
special key disk. In recent years, copy protection has fallen into disfavor since
it often introduces many complications for legitimate users. It is important to note
that copy protection is not the same as copyright. Even if an item is not copy protected, it may still be copyrighted
and therefore illegal to duplicate the material.