I'm for this option if and only if it is configurable. I wish to follow only a fraction of the threads where I click "like" (or the like), and I don't at all mind just going up to click "Watch Thread" up at the top. I do not care at all to have to go up and click "Unwatch Thread" every time I simply "liked" a post (or found something funny or helpful or what have you). That's a lot of extra clicking to avoid a tremendous number of unwanted notifications.
If it is not something that can be turned off, then I am dead against it. I don't at all care for automatically imposed micromanagement.
To be fully honest, I'm not to thrilled about having to unfollow as many threads as I do, simply because I replied. Threads inevitably go off the rails into several other discussions that have minimal or no relationship to the original topic, and I often need to unwatch many threads long before they just die out. However, it's a fairly small pain that I tolerate easily.
