Beyond what has been posted here so far: wiki posts are, like Wikipedia or WikiTravel, maintained by the community; it's not delegated to moderators or even the creator of a wikipost, it's crowd sourced to the "FlyerTalk brain trust" of knowledgeable members.

Any signed in member with ninety posts and ninety days of membership can edit (or create) a wikipost. This keeps "mega threads" user friendlier, and can be useful to summarize information, direct attention to specific posts, etc.

I just authored a wikipost for this thread (see above), adding a bit of boilerplate I like to include to start, then other information good for a mega thread wikipost.

Wiki posts are a relatively new tool for making the FT knowledge base easily accessible to all of us.