I subscribe to a variety of non-default reddits: /r/programming, /r/python, /r/android, /r/programmerhumor, /r/gaming, /r/truegaming.

I'm also a mod of /r/science and /r/askscience.

I enjoy a few extra ones, such as /r/askhistory, /r/cleveland, and /r/daystrominstitute (star trek discussion), but usually browse them once every week or so. Other than that, my interaction with reddit has decreased over the years. I could say the same about Twitter and Facebook too.