TL;DR: No, it is not necessaryit is not necessary to include "tags" in question titles.
Stack Exchange sites have an extensive tagging system which allows users to identify what subjects are involved in a question, watch or ignore certain subjects, narrow their searches to a specific area, and even learn about the tag's subject via its wiki.
This tag system works. You can rely on it to notify users who are interested in a tag about your question. Stack Exchange is optimized so that tags are indexed by search engines along with the content of the question. Users are guaranteed to be shown your tags, and will usually take them into account when answering your question.
As a matter of fact, the system automatically prepends the most commonly used tag to the question title when generating the page title (unless it's already in the question title somewhere) to help search engines find it more easily. (This doesn't happen on meta sites, but it doesn't matter since the most common tag is probably one of the four required tags anyway.)
Therefore, it is completely unnecessary to include tags in your question titles.
You absolutely do NOT have to use any one of the following forms when composing your title:
- [tag]: [question title]
- [question title] -- [tag] [tag] [tag]
- [question title] in [tag]
- [tag] [tag] [question title] [tag] [tag] [tag]
- [tag] [tag] [tag] [tag] [tag] [tag] [tag] [tag]
The only time you should use tags in your title is when they are organic to the conversational tone of the title.
For example,
JavaScript, jQuery: When should I use one or the other?
is seen by many users as an attempt to force tags in order to compensate for a lousy title. The title would be much more well-received if rewritten like this:
Can I use plain JavaScript to foo the bar on the baz, or is my only choice to use jQuery?
