Re: mDAUs
"So if the process they use to define an account as an mDAU inherently means that pretty much no bots get selected, then it massively skews that figure."
That's a lot of cheating to try and get away with for the long term.
A good metric would be an account that is logged into a certain number of times per week that follows a certain number of other accounts and the user posts a certain number of posts. If you want to look for bots, accounts that meet the above criteria but never respond in a meaningful way to another user's posts might be a redneck, err, bot.