I have been in similar situations a couple of times in the past. There's nothing wrong with it, I only caution you not to be taken for granted...
- you have no obligation to answer their questions - only answer if you want to
- feel free to ignore requests for additional details, explanations, etc.
- remember that the site works on Q&A where questions are in posts, not comments, and anyone can answer.
So, that's my only caution - to remember that you are answering questions to satisfy your own motivations... whatever those may be. If you fall in to the trap of answering questions to satisfy other people's needs/demands, then you'll not have the "fun" this site should be. It should not be a "chore" (and there have been times in the past where the site has felt like a chore - so I speak from experience when I recommend caution).
Having cautioned you for the traps, the upside is that if you establish a sequence of answers you can really see the positive impacts you can have on other people's learning, and it is very satisfying when you feel you have helped someone like that. The reputation/internet points are a bonus (well deserved, but still just a bonus).