It is very possible and was what I was going to do originally. However, I was worried that there would be thousands of subreddits to scrape, so I decided to just go with the top ones in terms of size. There are also a few that are included because they're interesting to me.

In the future I will either have a subreddit suggestion form or a way to only see the subreddits you're subscribed to. I really just wanted to get it out there and see if there was any interest before I put more effort into it.