Commercial Software
Software which is fully working, usually sold by the author (usually a company) for profit. Redistribution, copying, modifying, and so on, is usually prohibited. User manuals usually accompany the software in printed form (though some companies use text files on disk). Commercial software is usually found in computer stores, from a distributor, mail-order outfit, or direct from the author.

Crippleware
Shareware which has features disabled as an incentive to pay the author his or her "registration fee."

Demo Software
Software provided as a "try before you buy" measure to see if the software lives up to your needs and expectations. This type of software is usually crippled, but has enough of it working to get an idea of how it works. Documentation is usually thin, if at all present. The demo version usually has as its counterpart, the commercial version.

Freely Distributable
Software which may be distributed according to terms presented at the original distribution site, and/or within the archive containing the software. The author usually retains copyrights, et. al., and there is usually a clause against modifying the software, or at least modifying the software and redistributing it. Redistribution is almost always on a non-profit basis, with charges for copying (cost of materials like disks) being allowed.

Giftware
Software, usually under the same terms as Shareware, usually with no restrictions, which the author requests a gift for. Many times you can send money (an amount you feel deserving), or records, CDs, tapes, videos, beer, cookies, and so on, as a registration fee.

Licenseware
Software which is usually "shareware" in uncrippled form, and distributed by a "Licensed Software Vendor." Redistribution by the general public is not allowed. Fees paid to the vendor, are usually split between the vendor and author of the software. Terms and conditions are usually like those found in commercial software.

Public Domain (PD)
Software which has been entered into the public domain. The author has given up all rights to the software. You may sell it, modify it, redistribute it, burn it, and so on. You can do anything you want to the software (except copyright it, since it is "PD").

Once software has entered the public domain, it cannot go back. It is forever free. HOWEVER, if a new version is released (updates, etc.), then the status may be changed. A simple change in something like the name or author may not be enough, but changes or upgrades in functionality usually are.

This type of software is usually the only type in which the author gives up his or her rights. For the other types of software here, the author usually retains full rights, including copyright, unless otherwise noted by the author.

Shareware
Software for which an author has requested a sum of money be returned to him/her. Distribution is as described in Freely Distributable software, or may fall under other terms and conditions.

Sometimes the software may be complete, with all features enabled, or with certain features (like save and print) disabled. This is commonly referred to as "crippleware." Sometimes, there is a timed requester which pops up to remind you to register (you usually must click an "ok" gadget to continue).

________ware
Fill in the blank on this one. Usually whatever is added where the blank line is, is requested as payment. Examples are, Beerware, E-mailware, Postcardware, and so on. This type of "shareware" is usually cripple free, though some authors will have a requester version publicly available, and a version without a requester when you register.