I noticed that on SO many users would ask a question but forget or don't know that they need to provide more info (e.g. about setting, environment, etc.). To better elaborate my point here is an example for tag sql.
In more than 80% of the questions asked, the OP would not list very important info that would help answering their question, such as:
- which DBMS is being used
- whats the table structure
- whats the error message
So my suggestion is that when a tag is assigned to a post a list of hints would pop up, suggesting to the user to add some info if he didn't (in my example above: the hints would be: point out which DBMS are you using, list the table structure if its needed to answer your question, etc.