I think the reason to not receiving notifications for all the new threads may be is that you are not much active on the Announcements (Altcoins) sub-board, meaning that you did not browse through this board recently.
The notification emails clearly state this :
More topics may be posted, but you won't receive more email notifications until you return to the board and read some of them.
I always check the sub-board but not by clicking the link in the email.
I will click all links and we will see what will happen.
