Possible Duplicate:
How do favorite questions work?
Can I get “Notify” on selected question
Mark questions to receive notifications and updates?
Is there a way to get notification about the subsequent activities of a question that you commented on on Stack Overflow?
Secondly, is there a way to follow an unanswered question if you are interested in the answer?
Favoriting should* work for these, here is the FAQ.
2.Changes to the question will now notify users who have favorited the question. Notifications include comments to the question, edits, new answers, and edits to answers. This is a way to get updates on questions that you yourself didn't ask.
*: Apparently this was planned but has not yet been implemented. So until it is, there appears to be no way to get notifications.
In-site you can use favorites (click the star under the voting arrows on the question). Currently you will get a notification that you have favorite changes, but it doesn't tell you what changed or even what question has changes.
Every question also has an RSS feed you can subscribe to. Click the RSS icon at the bottom right of the page (with the "question feed" label), right below the Related question list in the right sidebar.
You can also check the "Allow email notifications when I subscribe to questions or tags" box in your user profile page (the Prefs tab), but this is global for the entire site and not individual questions.
As of today, you cannot get notifications like you want. They're working on it, apparently, but it's not ready yet.
