A few other forums I'm a member of when you post in a thread it automatically subscribes you to that thread so you can keep track of new posts. Is this feature possible or is it already there and I'm overlooking it?

When posting, select the "Enable email notification of replies?" Post Option.

Thanks Tarun. I'll look into it. Appreciate it.

My Controls -> Email Settings -> Enable 'Email Notification' by default

I unsubscribed from a thread a couple of days ago and am still getting email notifications everytime someone posts in the same thread. How do I stop this?

I don't want to disable email notifications altogether, I just don't want them from that one thread all the time unless I subscribe to it again.

Try in your User CP under Subscriptions on the left:
http://www.msfn.org/board/view-topic-subscriptions.html
http://www.msfn.org/board/view-forum-subscriptions.html

That was what I did. There were those instructions in each email to un-subscribe to a thread. In that "view topics"/"view thread", there are no more subsciptions listed but I'm still receiving the email notifications from the thread I un-subscribed to. Dunno if this process takes quite some time to take affect or what.

Have you tried going to the topic and choosing to stop tracking it from the Options dropdown?