What does "listening" mean in the Slate.com comments section?

Over at Slate.com, click on most articles and there is a somewhat obscured option to comment. This section reports “x comments” and “y people listening” What does the ‘people listening’ mean?

Go way back in the archives, Dec 2013, and there are reportedly ‘‘people listening’’. Photos: Open-air schools for sick kids in the early twentieth century for example.

I should have mentioned above, I have inquired of Slate and of Slate users and get no explanation.

I’ve assumed that it indicates the number of people who have clicked to open the comment section, and that it decrements automatically when you click elsewhere on the page to close the comments. That is what seems to happen for me, at least most of the time (e.g., the icon shows 8 people listening but when I open the comments, it increases to 9).

Hmm, actually the icon shows the number of comments, not the number of people listening. I do see the “___ people listening” bump up one whenever I open comments on a page though, so that’s still my best guess.

My ‘best guess’ too until I noticed that the same ‘listeners’ a month later. I subsequently did some brief snooping and found Red Lobster’s bad food problem: It’s egregious. which has about 199 'listening. There are not 200 people viewing comments on a Dec '13 article about red lobster. Something must be hung up in the data.