Last night, Ragan Haggard of Sun Microsystems told STC Austin about his journey producing documentation for OpenDS (an open source product) using only wikis. From the myriad available, they picked a wiki -- JSPwiki -- that met their key requirements (still in active development , syntax, rich text, content control); however, not even the best-in-class commercial wiki, Confluence, could offer the Section 508 (accessibility) and commercial quality PDF book output they still need. (He hadn't heard of FLOSS manuals, although that's still not the holy grail.)

Their open source documentation site is OpenDS.org/wiki; the team consists of 3 writers and 1 manager, along with Sun SME contributors. Text formatting in JSPwiki is done in wikitext, which is a simple (well, simpler than HTML) text markup for creating structured formatting (see the Rules for text formatting, to get an idea). Wikitext limitations, such as in creating complex list structures, were one of the downsides of using JSPwiki; other problems were the painfulness of renaming pages and the lack of email pings for changed pages. About their processes:

• New articles are generally written and reviewed before being added to the live wiki.
• The Recent changes page is most helpful for wiki administration (not users), to scan for spam. 
• Product versioning is "snapshot and freeze": at release time, they copy and lock the wiki at that version number (lock to users: Sun folks can still update).
• To get the conditional print output they need, they're working out a DocBook export and development process.
• Sun-branded wikis are Confluence-based: wikis.sun.com

Promising! While I couldn't get a good sense of how their product versioning strategy could work for a product like ours (the company working on the future release's wiki while the user community is adding content to the current releases' wikis, and how to synchronize across them?), I think it could work for wiki-based documentation development that occurs within the company only (which in fact is what the OpenDS folks were doing: no significant non-Sun participation). The wikis (one per major point release) would be the single source for non-HTML outputs and themselves be the HTML output for released versions; the future-facing wiki would be hidden from users until release time. This way, Support, Consulting, Training -- everyone -- could make fixes and improvements in real time across the comprehensive product doc set (admittedly, some fixes would need to be made in multiple wikis). The one thing that's missing -- and it's huge -- is a wikislicing solution that allows for remixing and reuse across these wikis, and with lovely print publications (full front and back matter) at the end of it.

Ragan said that the biggest reason the wiki fad will endure is the huge leap in quality brought by collaborative authoring: More eyes, more brains, more hands, more useful content. I think he's spot on, there. It's more when than if, I think, just waiting for toolset maturity.