Despite the popularity of m_goldberg's proposal I have misgivings about eliminating the error tag by way of making it a synonym. I offer a counter-proposal in my own answer. Please vote it up or down accordingly.
The summaries read:
Questions seeking help understanding error messages and fixing errors.
For questions on interpreting existing error messages that you have encountered, as well as writing and managing messages, ...
We also have messages with 29 questions and a summary of:
- Questions on the internal error messages of Mathematica.
Clearly there is duplication, but also some things are missing:
- Not all messages are errors
- Not all errors produce messages
I think these tags need to be reorganized and clarified. I am soliciting proposals.