The heart indicates a topic that you have bookmarked or was bookmarked automatically because you posted it.You can edit your bookmarks by going to my bigtent > bookmarks.
The "new" icon indicates that the topic you are viewing is new or has a new comment.
The chili pepper indicates that the forum topic in question has a relatively high number of views and comments, or has been voted "must read" by several members. It is a way to pinpoint which forum topics have the most activity within the forum - your group's "hot topics." If you only have a couple of minutes to see what's new with your group, following the chili pepper is a good place to start.
The star indicates a post that has been voted "timeless wisdom" by your group.
The lock indicates that the topic contains private comments, only visible to you.