For example in ikiwiki's notion of time, should one remove the text about the implementation bug that has been fixed, or should it stay there, for reference? --tschwinge

I have no problem with cleaning up obsolete stuff in the forum, tips, etc. --Joey

That's also what I think: such discussions or comments on forum discussion pages, or generally on all pages' Discussion subpages, can be removed if either they're simply not valid / interesting / ... anymore, or if they've been used to improve the real documentation. --tschwinge