Bolzano is a program for running a wiki. A wiki is a web site designed to encourage people to contribute to it. The most famous wiki is Wikipedia, but there are many others. The first wiki, designed by Ward Cunningham in 1995, is still running at http://c2.com/cgi/wiki.
That's a photo, not a cartoon!
The point of Bolzano is to illustrate what I think is about the right set of features for a wiki program to have.
Bolzano strikes the right balance (according to me) between features and complexity: enough features to get on with lots of collaborative communication, but not enough features to distract us while we're trying to write. In this respect it's very much like Ward Cunningham's original wiki program, as opposed to impressive but relatively difficult to use wikis like MediaWiki (which runs Wikipedia).
Bolzano's main features:
Most importantly, it doesn't have creeping featuritis. See "Deliberate limitations" below: they're important.
Its markup language is simple, and hence easy to learn.
It uses Unicode for everything including page names, which makes it especially suitable for non-English languages.
It saves a complete history of page changes in a compact human-readable format (working, but currently using an external program; to be implemented directly in Bolzano eventually).
Bolzano is password-protected, but it only has one password. Users can't have separate accounts (although they can enter their names when they log in, and these names are noted on the site history page).
Most wikis allow you to write a link with a title that's different from the page name or URL, so that, for example, you can replace a long URL with a single word.
Like the original wiki (http://www.c2.com/cgi/wiki?WelcomeVisitors), Bolzano disallows this. (That sentence makes a good example. In most wikis, you could abbreviate that link to something shorter, but in Bolzano you can't.)
This restriction is completely deliberate, and it has a lot to do with what makes a wiki a wiki. A non-wiki web site should, ideally, look neat, and being able to give titles to links can help with that. But a wiki is different. A wiki should be optimised for making writing as easy as possible. That means minimising decisions. So the name of a link is the link itself. Nothing to think about there. Move along.
One complication to this limitation is that it's not actually enforced. Sometimes you really need to make these named links that I don't like, and when you need to you can. See the full Markdown syntax at http://daringfireball.net/projects/Markdown/syntax.php to see how. But if you find you're spending longer making your edits, then I'm going to say "I told you so".
Bolzano leaves as much as possible to the web browser. So, Bolzano doesn't give you a trail of breadcrumbs to tell you which pages you've visited. You're expected to be able to use your browser's Back function for that. And Bolzano doesn't give you a button to cancel an editing session. If you want to cancel an edit, just close the page.
Again, this lack of functionality is deliberate. You're best off if you learn how to use your browser properly, because your browser has uniform ways of doing things across all web sites. When individual web sites implement their own functionality, they do it differently from each other, and everyone gets confused and annoyed.
Bolzano uses only very simple programming techniques. For example, it keeps each page as a separate file on disk rather than in a database. This is also deliberate. For the reasons for this, see Bolzano technical apologia.