Hi, it seems that there is many people struggling with following Phabricator notifications. Being overwhelmed by notifications defeats the purpose of notifications. :)
This is an invitation to share some thoughts.
The main trick is of course to pay attention to what you subscribe/unsubscribe to. Sometimes I ask myself: why am I receiving this notification, and after a quick investigation it turns out that I am still watching some project that I am not really interested anymore, or at least not at the extent that it would impede me to follow better the projects that I really want to follow.
I actually unsubscribe from many tasks, and that keeps the signal high vs noise ratio high.
Email preferences can also help a lot reducing the amount of (what for you constitutes) noise. Also, many people seem to struggle with volume of emails received and haven't really tried the alternative of web notifications, which (at least for me) allow for quicker scanning + the fabulous button "Mark all as read".
I also set many types of notifications to "ignore", because for me at least the information they bring doesn't compensate for the noise they create. I have copied my Maniphest email preferences at https://www.mediawiki.org/wiki/User:Qgil-WMF/Sandbox just in case someone finds them useful.