I signed up here a couple of days ago, and it appears that I’ve received an email for every new thread created since then.
I looked in my discourse user prefs, and turned a few things down (automatically tracking things that I spend 4mins time in), but it didn’t stop the new thread emails.
It turns out that required managing prefs from the email unsubscribe link (well, I hope it worked). In that prefs form there was a “Disable Mailing List mode” checkbox which I ticked - I assume this refers to the way a Mailing List subscription exposes you to every email sent to that list.
In my experience (20+ years on various different BB style forums), every forum I’ve ever joined makes the assumption that I will opt-in to any discussions I want to follow - I found this default “Mailing List enabled” mode means I have to opt-out (of every discussion, or I presume by disabling the Mailing List mode), and just a bit annoying.
My feature request is to set Mailing List mode=disabled by default (obviously pending forum manager agreement/weight of public opinion)