A year and a half ago, I did two posts about wikis: "Collaboration Between Law Firms Using Wikis" and "Wikis as a Repository of Legal Know-How." Back then, wikis were just taking off, perhaps thanks to Wikipedia. Now they are ubiquitous, though not necessarily among lawyers.
A good update to my earlier posts is an article at Law Practice Today: "Wikis for the Legal Profession," by Dennis Kennedy and Tom Mighell. It starts like this--
Why should lawyers use wikis? They may help lawyers both as consumers and as producers. Most lawyers will get the most value from using wikis created by others. The classic example is the Wikipedia. Wikis can be seen as constantly updated collections of useful information arranged in an encyclopedic or similarly organized way, with hyperlinks to related internal and external information.
On the producer side, perhaps the greatest potential of the wiki tool for lawyers is its use as a collaborative tool or even an information or knowledge platform, especially as a way to gather and manage "unstructured" information easily and quickly. The key feature of wikis in this regard is that multiple authors and editors are able to work together to create a collection of information or even collaborative documents.
The piece goes on to define wikis, explain their uses, and list a number of important resources.
Password-protected wikis as a tool for collaboration among law firms still makes sense to me. A caveat is that the wiki must become the sole platform for collecting and disseminating information about the project. Otherwise, at least in my experience, people at each firm will be tempted to set up their own overlapping and competing systems, using software they are more familiar and comfortable with but which lacks the collaborative power of wikis. Meanwhile, the wiki will languish.
If you're going to use a wiki to share and manipulate information, start with the Kennedy-Mighell article, then make sure that all users are firmly on board, committed to the wiki both in concept and in practice.