Here’s a half dozen interesting options for the multi-author collaborative website

• SeedWiki
  Not as visually sexy as some of the others, SeedWiki charges for privacy. Looks like wiki’s are public and open to anyone with a seedwiki account by default. Either $10 or $20/month buys you domain mapping (for rebranding) and some access control. This one seems the least polished of the list.
• StikiPad
  At it’s core, StikiPad is a wiki. A well-thought out, straight forward, ruby-on-rails, hosted wiki. A common sense text-formatting legend is clearly displayed next to the edit box. An unlimited number of authors gain access through an email invitation and they’ll need to create a password. Everybody gets a profile page. All the pages support commenting as well as editing, tagging, and searching. Phew. $15/month includes a 1/2 gig of storage, an unlimited number of wikis, complete CSS control & templating & domain mapping (great for re-branding). This is my favorite in the list.
• JotSpot
  This is a wiki and all that means – content over presentation, low usability as the barrier to entry. JotSpot doesn’t like Safari that much (everyone else on this list hates IE). The site feels slower than everyone else and the visual design and text-formatting aren’t as straight forward or sophisticated as the other sites on this list. Each wiki page supports comments and file attachments. Invitations to other authors is handled via email. $70/month for unlimited authors, and a thousand pages. But hey – every plan is free for two weeks. Makes me think you start one for the event, see how popular it is, and pay the appropriate monthly fee for archiving.
• Backpack
  Far more structured than a wiki, Backpack is a hosted service with explicit sections for lists, notes, pictures, urls, files, and 37sigs’ Writeboards (like a wiki). Pages can be made public and and it looks like any number of people could edit them (via an email invitation) They’ll probably need to create a password. $19/month supports 1,000 pages and a 1/2 gig o’ storage.
• Campfire
  The recently launched browser-based hosted chat again from our friends at 37Signals. It boasts permanent urls for each chat, file upload and sharing, search, image previews, and a dead simple login process (“Enter Your Name”). $49/month buys you and 39 of your friends a gig of server space and one big simultaneous conversation. What if we had 80 people? Dunno. Jason?
• SocialText
  SocialText has a hosted service called ‘EventSpace‘, sounds promising. It’s got a chat, wiki, and a weblog (depending on what feels right at the time), bios pages for everyone. As you can see from the Web 2.0 Conference and SuperNova sites, the system is very comprehensive though the branding and visual design leaves something to be desired. This sounds like it’s got everything – except a price tag on the site. Hmmm.