A super-brief version of the article Knowledge sharing in practice, on the wiki:

• Encourage contributors, especially knowledgeable people.
• Use an open license – that’s a real open license, no Non-Commercial or No derivatives clauses).
• Use open standards and open formats. Do not use PDFs unless you also make it available in (say) HTML. And a wooden spoon to those sites that require specific software, often restricted to Windows and/or Mac. Tsk tsk.
• Use a wiki.
  • Use an existing wiki where appropriate – they’ll be thrilled to have you.
  • You need several highly focused people working on it daily, and you need to avoid re-inventing the wheel.
  • Make it open edit.

Also on the wiki:

• Open knowledge