It can be very hard to get started with a wiki - content either isn't added, or isn't up to date, so people lose trust in the info in there. This has a negative feedback effect on people writing entries too. In addition, writing articles is hard as people feel expected (perhaps from wikipedia) to having to write detailed, canonical articles.
I have had success numerous times introducing an internal blog as a team knowledge repository, blogging anything interesting to it. With a search function, and making anyone an editor, it has many of the same features with a number of benefits:
- people can comment and ask questions
- signing up the development mailing list as an email subscriber ensures everyone sees new info as it is posted
- people blog about code issues, and tips and trick, not just 'how complicated feature X works'
Honestly, it works a treat. Blogging is the mechanism by which we share programming knowledge on the internet, why shouldn't it be the method we use inside our workplaces?