Yeah I agree the format is unreadable for github users .The reason is like that is that it makes merges more fine grained. Indeed a fileout will give you what you want. You can also use gist which will make it easier for them to view and you won't have to version control it.
The playground also has a way of posting snippets online. Downloading and using Pharo is an alternative. You can distribute your project via Catalog Browser which will make it a one click install, the it's just a matter of using the browse message. Or you can make a small piece of Smalltalk code that installs and opens the browser to the class and method you want to show. You could even hack the profstef tutorial for a small demonstration .
