If you click it, a small menu will pop up, showing you all our current prefixes:
What does each prefix mean?
OPEN: This thread is open to anyone who might wish to join. You must either include this prefix or PRIVATE.
PRIVATE: This thread should ONLY be posted in by people who are invited. Often these will take place in private areas, such as someone's house, where no one could just 'walk in' on them. You must either include this prefix or OPEN.
EVENT: This thread is part of one of the many site events! It could be either the main event thread, or a thread that has split off from it. Generally the description of the thread should indicate what event it's part of. Please be sure to also include whether your EVENT thread is OPEN or PRIVATE.
MATURE: This prefix is unique, because it doesn't directly indicate what type of thread, but instead is used in addition to the other prefixes. This means that the thread goes past the PG-13 limit, and is thus only accessible to those over 18 years of age. You must also indicate whether your thread is OPEN or PRIVATE.
FINISHED: When your thread is over, you must mark it as FINISHED. Feel free to remove the OPEN or PRIVATE tag, since threads should not be joined or roleplayed in once finished.
ALT: What do 'OPEN' 'MATURE' 'PRIVATE' and 'EVENT' mean in front of a post? What makes a thread private?