Isn't there a little x in O you can click to delete it?
Persistent Alerts - I have one from my club won't go away no matter how clicked

Hey Batgirl thanks for being a normal thinking person.
Yeh I've unchecked the X 20 or so times it keeps coming back.
It's Dragonblasterskeletor club whatever has a new topic. Yay for bluetack!

Are you being a mutt to me as well Hoff? but we are friends? : / Perhaps you two should find some flies to pull the legs off or something.

Hey Batgirl thanks for being a normal thinking person.
Yeh I've unchecked the X 20 or so times it keeps coming back.
It's Dragonblasterskeletor club whatever has a new topic. Yay for bluetack!
Ok, that's worked for me in the past. Maybe a bug report is in order?

Opera was good but after I installed a 3rd party twitch thingy it's screwed now lol. I guess I should dump it and get a brand new packet

Yeh, tricky. I'm a bit loathe to create bug reports as I'm in linux, what percentage of people on chess.com are on linux I wonder. Probably more than other sites
¯\_(ツ)_/¯

One of the clubs I’m in is always alerting me that a note was posted. Members are always saying “hello” to each other. That could be what you’re noticing.
You can go to that club’s home page and disable the note posted alert switch.

No no... this is a new TOPIC. why are women so much better at reading comprehension in this thread than men? you guys are in trouble if we ever manage to translate this advantage into chess.

What exactly is the notification? Notifications show up in a certain section on the hotbar, you click the X and it disappears. The same notification for example from a Forum thread appears if you have commented on it and someone then makes a new comment on it. In that case you will keep receiving a notification until you unfollow it.
But I'm not sure what the notification is, maybe it's not forum related.
Please read OP title twice or wear glasses, she said " it is about the club".
It's annoying.