The usual guidelines about tags suggest to use tags that:
- don't say anything about the user who is asking the question
- describe a specific area of expertise
For example, beginner is a tag that describes the user who asks the question, not the question itself. error doesn't describe a specific area of Drupal expertise. Differently, views describes a specific area of expertise, in the same way cck does.
Keep in mind that not everything in a question needs to be captured with a tag; tags are for the most important parts of the question. Considering there is a limit of 5 tags per question, we need to limit the tags to those that are really helpful, which don't apply to 50/60% of the questions (or more), but not even to very few questions.