I'm splitting this question off from the original question, Are wood identification questions allowed?, because the answers to that question only addressed wood identification and not the other identification questions that I had really hoped to address.
For example, if someone posts a picture of something besides wood (e.g., a tool or joinery), how should that be handled?
I think I recall some SE sites discouraging identification questions as too localized because they end up being only useful to the asker and are phrased in terms of, "What is this?" which doesn't help with searching. Maybe the OP has a guess at what the tool is, but maybe not.
If we allow identification questions, should each one be tagged with the answer and/or should the title be edited afterward to reflect the answer?
Example (before):
What is this tool?
<picture>
tags: hand-tool
Example (after):
What kind of hand tool is this? [Yankee drill]
<picture>
tags: drill, tool-identification, hand-tool
I'm still not sure this solves the problem, but perhaps someone browsing through the questions tagged with tool-identification could run across the tool that they want to identify, or maybe having the name in the title will jog their memory.
Here are a couple recent identification questions:
Is this a specific kind of hand drill? (good title)
What is the name of the corner joint with grooves on this chair? (title should describe the joint)
Any other suggestions on how to handle these types of questions and how to make them more useful to future visitors?