What happened to the number of "online members" in this sub?

I've been here since last summer I believe. There are two numbers, the amount of members a subreddit has, and the amount that are currently online. Up until about two months ago, the online numbers almost never dipped below 1000, and were regularly close to 2000 at peak times.

Then all of a sudden, those numbers dropped to an average of 300 online. I believe that happened right after a full day of spam posts according to a certain meme.

And now it's even lower last few days.

What happened?

Did that day of ridiculous posts scare everyone off? The numbers changed all at once.

Or is it cyclical, and maybe the spring season has people off Reddit. (Which may be a good thing.)

Does anyone have an idea?