1. That's fine, most ppl don't need the answer now, they need it soon enough to not be blocked.

2. Any answer without context is useless, even verbally. So include the question with the answer when you write the doc.

3. Internal wikis are inherently trees, add the answer to an existing node or create a new node.

I see most of these replies are failing wiki docs for not being perfect - you just need to be good enough. It's a living document, as it's used it will mature. The important part is capturing the information somehow, somewhere.

Stop propagating tribal knowledge and document it!