I've been thinking here... we really have good tools like mentioned by @Hypnotizer, but in fact it is a third party services and even though they are reliable, there are people that do not like or simply do not trust in external toolsto bitcointalk.
What kind of trust does any of those tools require? You either need to use telegram (>1 billion users), SimpleX, or a simple web page.

I use the watch list to check new topics or recent active topics, but it's no good for keeping track of who quoted/replied you. Also, there are no notifications... you need to visit the page. More like different purposes.