I'd second what @mk4 suggest, even this forum have watchlist but it doesn't look friendly to use.
Isn't it easy to use? It's one of the best functions the forum has. I can say that 90% of my browsing is done based on my watch list.
Basically, when I enter the forum, I click on my watch list, choose a topic that has received responses since the last time, read the topic (I will respond if necessary) and return to the watch list.
I find it difficult to find a simpler and more efficient method than this. Much better than having an endless list of topics in my browser favorites.
How to bookmark a post or thread in this site, if I like a thread and want to bookmark it or save it like twitter , ?
What you intend, already exists on the forum, is what you find in all the topics on the forum. When you enter the topic, at the top of the first post on the page you will find the following:
When you click on "watch", the topic enters your watch list, and whenever a new post appears since the last time you saw it, the topic appears in your list.
To access the watch list, simply follow the following link in the forum header:
https://bitcointalk.org/index.php?action=watchlistEDIT:
Of course, if you want to save a specific topic, so you never lose it regardless of how much time passes, saving that topic in your browser's favorites is the solution.