It does allow you to watch a question. Check your profile for more.
You will see a favorites tab on your profile. Clicking on it will show the list of questions you either want to come back to or track in some way.
When you click that star it does allow you to track the activity on it.
You may notice after a while, when logged in, the tab may have a number next to it
summary | answers | questions | tags | badges | 3 favorites | etc.
That number tells you how many questions have had new activity since you last checked. That could be edits or new answers.