Subscriptions are forums or individual topics that you have elected to watch for any new posts. Whenever a new post is made inside an area you have subscribed to, an e-mail will be sent you to informing you of the new addition. To create a subscription, visit the forum or topic you would like to subscribe to and click the 'Subscribe' link located at the bottom of the page.
To remove a subscription, check the box next to the subscription you would like to remove and click the 'Unsubscribe' button.
Bookmarks, much like subscriptions, are topics you've chosen to watch. However, there are two key differences: 1) only individual topics may be bookmarked, and 2) an e-mail will not be sent to inform you of new posts.
To create a bookmark, visit the topic you would like to watch and click the 'Bookmark Topic' link located at the bottom of the page.
To remove a bookmark, check the box next to the bookmark you would like to remove and click the 'Remove marked bookmarks' button.