I have never used the word “shareware” to describe Bingo Card Creator, because I think that it is an anacronism that my customers do not understand, but among fellow technically inclined people it describes the business model succinctly.  Someone visits your website, downloads your trial, and hopefully purchases your program.  That process is called a funnel, and if you break it down into concrete steps, the shareware funnel is long and arduous for the consumer:

1. Start your web session on Google, like everyone does these days.
2. Google your pain point.
3. Click on the search result to the shareware site.
4. Read a little, realize they have software that solves your problem.
5. Mentally evaluate whether the software works on your system.
6. Click on the download button.
7. Wait while it downloads.
8. Close your browser.
9. Try to find the file on your hard disk.
10. Execute the installer.
11. Click through six screens that no one in the history of man has ever read.
12. Execute the program.
13. Get dumped at the main screen.
14. Play around, fall in love.
15. Potentially weeks pass.
16. Find your way back to the shareware site.  Check out price.
17. Type in your credit card details.  Hit Checkout.

I could go into more detail if I wanted, but that is seventeen different opportunities for the shareware developer to fail.