When is it appropriate for me to use a community wiki?
Virtually never. The feature has been almost completely deprecated.
Marking an entire thread Community Wiki is no longer supported, and using Community Wiki to lower the reputation needed to edit a "community post" has been replaced by the 'suggested edit' feature — so the use of Community Wiki is no longer recommended.
Before it comes up, here are a few other issues to consider about using the Community Wiki setting:
- Community Wiki should never be used to deprive a user of reputation
e.g. "You don't deserve reputation for this, so we're going to make it Community Wiki." - Community Wiki should never be used to "tolerate" a post that otherwise would not be allowed
e.g. "We don't generally allow questions like this, but if we make it Community Wiki, it should be okay." - Community Wiki isn't a way to forgo the reputation system
Users should own their words in Q&A (incidentally, opinions expressed in meta do not generate reputation). If a users has the habit of posting and then disassociating themselves from the residual impact of what they say, they may no longer be allowed to participate. - If your post has been forced to Community Wiki (by the system or by a Moderator), simply 'flag' it for Moderator attention and the ownership/reputation should be restored without hesitation.
Incidentally, there really shouldn't be any more automatic Wiki-conversion triggers left in the system, so I don't suspect this will actually apply here.