WikiServer

I've played around with MediaWiki and AppleWiki instances and always seem to migrate back to hosted, cloud-based platforms like TiddlySpace...the fact that you can host your own TiddyWeb server is just icing on the pie!

what distinguishes other servers from TiddlySpace:

MediaWiki has a large, active user base thanks to sites like Wikipedia
AppleWiki has wiki/blog integration and video integration (PodcastProducer)
Wikispaces is admittedly a no-brainer to use - expect more of a rampup curve using TiddlySpace

finer details of what distinguishes the TiddlyEcosystem:

you can render pure HTML like this example
encourages synthesis (see Facebook)
allows individual tiddlers to be private (no need to pay $20/month to Wikispaces)
allows you to host your own server (this can be critical with education where sandboxing inside school firewall is a requirement)
CamelCase rocks to both foreshadow future links and it just saves time (no more editing just to turn a link into a hyperlink)
tiddler-based programmatic plug-in model
multi-layer hacking - at the TiddlyWeb (server), client (TiddlyWiki), structural/CSS (StyleSheet), content (tiddlers themselves) and collaborative (TiddlySpace) - you'll find the hacker in you :)
offline operation on iOS platform via TWEdit
TiddlyWiki is easily skinnable - very sophisticated content-synthesis model for tiddlers themselves - very easily ported DanceChalat tiddlers into default TiddlySpace skin
HTML embeds (GoogleVideo, GoogleVoice, Flickr) are trivial
Tiddlers can move freely from one space to another - when one has created sufficient content to justify a separate space - extremely easy to do
wikitext formatting
revision of tiddlers built into server architecture
tiddlers work at the micro-level (think micro-blogging like Twitter)
tags will cross-reference to their tiddlers
multiple tiddlers can be edited at once - supports refactoring and parallelism
double-click to edit - nice!

This paradigm supports the Geek in everyone ;-)