My requirements for the wiki were the following:
- Topic articles with versioning, attachments and discussions;
- Authoring of articles by invitation only, discussions opened to everyone;
- Hierarchical organisation of topics, ideally presented like online help: table of contents, index, search;
- Customisable UI (branding);
- Full-text search;
- Authoring using Word;
- Preferably a hosted service with a friendly URL,
- Authoring of articles by the owner of the blog only;
- Organisation by category and by date.
http://www.wikimatrix.org/ is an invaluable resource to compare wiki software and two hosted solutions rise above average: jotspot and stikipad, although neither of them fulfils 100% of my requirements. Both products are basic but they do the job although authoring in Word, my top requirement, is not possible with these wikis.
I have not been able to find a comprehensive resource that compares blog software properly although there is some information at http://www.cmsmatrix.org/. The well-known products I have come across are Community Server (formerly .Text), Moveable Type and WordPress. The top services are Blogger, MySpace and MSN Spaces. There is now also a Yahoo offering based on Moveable Type. My preference is Blogger because there is a Word plug-in which works reasonably well and it is free. The main objection is that Blogger lacks proper categories.
My conclusion is that there is still a lot to improve on wikis and blogs especially to streamline the authoring process and to make navigation more fluid.