If we were to implement tagging for questions, would you like a Tumblr-like tagging system ("something like this") or Twitter-like hashtags ("#hashtag")?
Whatever it is, make them a separate field. Nobody likes #Hashtags #Littered throughout the #Input #Field
Retrospring uses Markdown for formatting
*italic text* for italic text
**bold text** for bold text
[link](https://example.com) for link