As of 12:56pm GMT (7:56am central time), 7742/8299 subreddits are no longer public
The information I initially posted is misleading. Thus, I have edited the title and this content area to report accurate numbers.
As @roofuskit mentioned, the 8299 number is the amount of subreddits that committed to going dark, not the total number of subreddits, which is over 3,000,000.
And as @8thiest was keen to observe, 204 of the top 250 are dark, as you can see from this site: https://save3rdpartyapps.com/
8479/8838 subreddits are currently dark as of 15.09 BST (British summer time).
This is so heartwarming. Haha, fuck spez.