I was definitely a Reddit power user. To the point that people who wanted to dig at me thought "look at all the time you spend on Reddit" would insult me for some reason. They lost me last week and I don't plan on coming back. I pinned a "Reddit sucks, come to Lemmy" post on my profile and logged out.
I won't say that I was keeping any decently-large subreddits alive singlehandedly, I didn't have that ability or power, but I was definitely a major contributor.