> Quick Google searches reveal that Reddit has something between 0.5 and 1.5 billion monthly users

Not disagree-ing with your points, but do you have a source for this? It doesn't pass the sniff test to me.

1.5B people is ~ 20% of the world population, and probably closer to 50% of those with computers & internet capable of downloading reddit.com, an image heavy forum.

I'm in the demographic for Reddit (30s, male, western country), and I think maybe 10% of my friends, family & coworkers even know what Reddit is, let along are an MAU.

Everybody's reporting "Reddit had 430 million monthly active users in 2020", so that's the half-billion that seems to be fact-based.

Then the current 1.5B number seems to be based on extrapolation (1.66B in [1] for one estimate) based on previous growth rates.

I shared your initial skepticism, but Reddit is the 20th most popular site in the world [2]. I know I have definitely been surprised and even shocked that certain extended family members and coworkers of mine have turned out to be heavy Reddit users. It's turned into this incredibly widespread site that almost nobody talks about "in real life".

Of course, monthly active users presumably includes people who click on a Reddit search result once in the month. It doesn't mean they're using it daily and upvoting.

[1] https://www.bankmycell.com/blog/number-of-reddit-users/#sect...

[2] https://www.similarweb.com/top-websites/

Does "user" mean "distinct human" or "user account" in this context? Need to keep in mind the culture of throwaways.

If 10% of users make a throwaway at a rate of 5 per month, then 100 monthly humans == 150 monthly usernames.

I highly doubt Reddit has 1.5B monthly users, otherwise they would have reported it in the media. Very few companies have the execution capabilities to reach 1B+ users