I have to maintain documentation on wikis as part of my work, and I hate it. And earlier today, as I was spitting expletives at my computer screen, I realized why I hate editing wikis so much: for the same reason that no one speaks Esperanto.
Every damn wiki system has its own peculiar formatting syntax. MoinMoin uses ''double quotes'' for italics and '''triple quotes''' for bold. TWiki uses _underscores_ for italics and *asterisks* for bold. Similarly (or, rather, dissimilarly), one uses ==double equals== for headings, but the other uses ==the same syntax== for bolded, monospaced font. (Figuring out which is which is left as an exercise for the reader.)
Don't even get me started on indentation.
There is no clear advantage to one wiki's formatting syntax over the other. It's a standards war (read: pissing contest), and nobody wins, especially not the user who has to work with multiple, different wiki installations and keep track of which nonsensical syntax he needs to use to just get some damn text on the freaking page.
Yes, I know this wouldn't be a problem if I was editing wikis all the time. But I don't. And the fact that simple text formatting-- not hyperlinks or tables, which are even more absurd-- is so damn unusable violates the purported simplicity of wikis for casual users. They're not simple. They're not easy. They are annoying.
Just let me write the damn HTML myself, so I can learn one standard to apply to multiple sites, or give me a WYSIWYG "compose" mode like Blogger does. Please.