I had some questions on this so I figured I would post the images and what they mean:
Two general points
- Red icons are unread items, blue/grey are read
- A star on any topic means you have posted in it
FORUM ICONS
READ FORUM ICONS

- Read Forum

- Read Forum (Locked)
UNREAD FORUM ICONS

- Unread Forum

- Unread Forum (Locked)
TOPIC ICONS
READ TOPIC ICONS

- Read Topic

- Read Topic (Posted)

- Read HOT Topic

- Read HOT Topic (Posted)

- Read Topic (Locked)

- Read Topic (Locked)(Posted)

- Moved Topic (if it was posted in the wrong place we might move it!)
UNREAD TOPIC ICONS

- Unread Topic

- Unread Topic (Posted)

- Unread HOT Topic

- Unread HOT Topic (Posted)

- Unread Topic (Locked)

- Unread Topic (Locked)(Posted)
ANNOUNCEMENTS ICONS
READ ANNOUNCEMENTS ICONS

- Read Announcement

- Read Announcement (Posted)

- Read Announcement (Locked)

- Read Announcement (Locked)(Posted)
UNREAD ANNOUNCEMENTS ICONS

- Unread Announcement

- Unread Announcement (Posted)

- Unread Announcement (Locked)

- Unread Announcement (Locked)(Posted)
STICKY TOPIC ICONS
READ STICKY TOPIC ICONS

- Read Sticky Topic

- Read Sticky Topic (Posted)

- Read Sticky Topic (Locked)

- Read Sticky Topic (Locked)(Posted)
UNREAD STICKY TOPIC ICONS

- Unread Sticky Topic

- Unread Sticky Topic (Posted)

- Unread Sticky Topic (Locked)

- Unread Sticky Topic (Locked)(Posted)