subscription vs buddies list

This may be a dumb question but since I searched PD and the Help forum with no luck,  I've broken down and am going to ask. What is the difference between subscribing to someone's art and adding them to your buddies list? What does the buddies list do that subscriptions doesn't and how do you know if someone has added you to their buddies list? If this has been answered before someone please point me to it  

The buddylist doesn't really do a whole lot. If you go to Members Area > Buddy List and click the Load Buddy List button it will show all of your buddies. It will also show which of your buddies are online. The buddy list is also used as a quick contacts list. When you are forwarding a private message you can select quickly from your buddy list. Also your buddies are displayed on your profile page.

The Subscribing to someone's art means you'll be notified when that user posts new artwork. It will appear at the top of the Members Portal page and will list all of the new artwork posted by people you've subscribed too. It's similar to DeviantArt's DevWatch feature.

Thank you for clearing that up for me.