I got rejected for a category extension board and they gave me the message "We require some level of activity before granting a category extension." I am wondering what level of activity is required to be granted a category extension.
There's no set level. But there should be some level of reason as to why you need a new board, rather than by adding new categories onto the current.
On a previous pair of leaderboards I've helped out with we were able to have Category Extensions page during a period with 30 active runners on the main board, if I remember correctly this also used to be the official requirement but that may have changed (made more or less strict idk) during Elo's time in charge.
I don't recall there ever being an exact cutoff, but yeah, 30-ish sounds reasonable. Honestly though if you don't have a pretty large group of consistently active runners you really don't need one at all. I moderate for a fairly active community and our category extension is just a wasteland of things that nobody cares about, I honestly wish we never made it. It was fun for a while, but now it's just a waste of time and energy for everyone involved
To add: I am a part of the haloruns community which has somewhere around 100-120 active runners at the moment. Our category extensions has around 2-3 runners, so if you can avoid it, add the category you want in the Misc. on your main board, or dont add the category at all.