How many of the 70k are bots?
Fair question. I think it's a pretty low percentage because it is still pretty niche, but I'm seeing more and more bots now that people have figured out how to make them.
ads
Don't understand what that has to do with anything.
If lemmy users are more likely to use ad blockers and whatnot, then the best way to target them is with SM posts. So if you know you're missing a certain percentage of potential customers, then it could make sense to change your advertising strategy.
For example, astroturfing may be more costly on a platform like Facebook than directly using the advertising platform, and it works because most users there don't block ads. Lemmy doesn't have ads, so the only way to advertise to those users would be through engagement with the platform.