I know that with the SimpleHTTPServer I can make my directories accessible by web-browsers via Internet. So, I run just one line of the code and, as a result, another person working on another computer can use his/her browser to see content of my directories.
But I wander if I can make more complicated things. For example, somebody uses his/her browser to load my Python program with a set of parameter (example.py?x=2&y=2) and, as a result, he/she sees the HTML page generated by the Python program (not the Python program).
I also wander if I can process html form submitted to the SimpleHTTPServer.
While it is possible, you have to do pretty much everything yourself (parsing request parameters, handle routing, etc).
If you are not looking to get experience in creating web-frameworks, but just want to create a small site you should probably use a minimalistic framework instead.
Try Bottle, a simple single-file web framework: http://bottlepy.org