Before the merge, I had not subscribed to anything from Ask Fedora, but was following some tags from Discussion such as silverblue.
After the merge, I started to get notifications from the Ask Fedora category for posts tagged with silverblue.
The great thing with merge is that it is not easily possible to watch everything with that tag if so desired,
but I am little suprised that I get notifications for things that I was not subscribed to earlier.
Is it possible to limit the subscriptions to certain categories only?
There is the option to mute a category, but going by the description, it does more than just stops notifications.
For what it is worth, I am not upset if the answer is that post-merge,
subscriptions just work a little different.
Then main problem here was that my email filtering broke and my inbox was filled with Ask Fedora notifications.
That problem is easily fixable by just updating the filter.