A few things I learned from setting up a wiki

Bringing together the learning points of my foray into wiki creation and administration (note: I'm (clearly) not an expert or anything, so my learning points may not necessarily be examples of absolute best practice):

1. If you need to compare wiki platforms, you could do far far worse than consult WikiMatrix. This tool lets you compare your choices from roughly 100 platforms across a range of attributes. It even has a handy Wiki Choice Wizard which helps you narrow down your choices.
2. If you're going to make test wikis, create them as test wikis and give them test names! You will inevitably find that you want to experiment with settings, and for certain fundamental settings (e.g. whether it's a business or individual wiki) you can't do so without deleting the wiki and starting over. For some services, PBwiki amongst them, once you delete a wiki the name becomes unavailable forever; so if you need to delete your test wiki, you don't want it carrying the name you were going to use for the real one!
3. Make sure you get in touch with any relevant Marketing and Communications or IT people to check that your wiki does not contravene their web marketing policy. This could be within your institution or, as was the case with me, within the organisation running the conference the wiki was for. Some talk beforehand about what you can and can't do will save you the hassle of re-writing later.
   
4. Consider giving freedom of writing access to your wiki. My wiki requires people to e-mail me (the administrator) to enable writing access, and it's turned out to be a real barrier to people editing and adding pages. Also, it's been extra work for me administering this aspect of the wiki (though I have enjoyed getting in touch with new users).
5. Don't just assume people will get in touch on the wiki - offer them reasons to interact with others, and make it easy for them to do so. I added a "Travelling together" page to the wiki to encourage users to club together for cab rides from the closest train station - it's been quite popular! I also added a template for creating a personal profile page.
   
6. Participate yourself if you want others to (that probably goes without saying). Comment, write, and add, and others will soon follow your example!

I could probably write a deal more, but for now, that's all, folks!