The essential content of this document was written by Peter N Lewis. It has been edited by Jeremy Nelson, one of Peter's employees. Peter is a successful shareware author best known for Anarchie and NetPresenz. Peter works full time on his shareware under the name Stairways Software.
The short answer is: Yes. But if you want to be successful at writing shareware, you should expect to put in more or less full time hours for several years - this is pretty much the same with starting up any business.
It is important to figure out what your goal is and work towards it. There are lots of different goals - fame; fortune; independence; a good job; etc. Figure out what you want and move in that direction.
I wanted to make a living writing shareware, and so I made decisions based on that - I didn't agree to lucrative exclusive deals that would have made me money at the expense of reaching that goal. But your goals may be different. You may just be after fame, in which case freeware may be a better route (although I have come to the conclusion that freeware is problematic since it is not self supporting, you eventually run out of time to work on it).
If you're after a good job, then a free or shareware program can be an excellent resume. If you're after making money, then write a program that competes with a Symantec program and maybe they'll buy you out.
On the positive side a shareware business is very low capital and hence very low risk - all you have to be able to do is figure out how to earn enough money to survive while you try to write your programs initially. And like any business, it takes a fair while to build up a client base (it took me four years of work before I earned enough to leave my day job).
How much money you receive depends on lots of factors:
Ok, so assuming you have a program that is high quality, that is addictive or useful enough that people will use it a lot, and that has little or no competition (or blows the competition out of the water). What can you do to improve sales?
Unless you have a program that will appeal to hundreds of thousands of people, you probably wont make any money. My suspicion is that only about 4% (or less) of people actually pay their shareware fees. I'm sure other authors could get a better rate by employing serial numbers and crippling/extra features and timeouts.
Carefully consider what price you charge. I generally recommend you charge $15 or $20. Kagi pretty much ensures you have a price for site licenses. Try to pick a program that will encourage companies to buy site licenses.
[Ed:Charging too small amounts is probably worse than charging too much. When the price is very low it becomes easier to justify away not paying; the bank will take most of it, I'm paying twice the cost of the software just in charges, I'm not depriving the author of that much money etc... Also companies often don't seem to have much faith in a product which is very inexpensive.]
Carefully consider what inducements you will include to "force" people to pay. I have very limited inducements, but I recommend authors have some form, such as serial numbers unlocking non-essential features, or better yet removing the shareware warning, mailing lists for updates, printed manuals, etc.
Do not disable the program or any significant portion of it's functionality. Time bombing the program forces the user to make a choice of paying now or never, and they will often choose never when they would have chosen later if you'd left that as an option. Remember that unlike commercial software (or perhaps just like commercial software), piracy generates sales.
[Ed: One very worthwhile web page to look at is < http://www.scrawlsoft.com/products/common/hardnose.html >, entitled "Why Do People Register, Does Crippling Work, Does Anybody Really Know?". The author of the article, Colin Messitt, actually tested whether crippling shareware works by putting out a program which, half the time, was crippled and the other of the time just had nag screens. Crippling the software caused a much higher registration rate.]