Here on TPA, we use various tags as part of post titles in order to show some information at a glance about a thread. Some show the thread type, and others show who can post in that thread. These can come before or after the thread title, but general preference is to put a thread type first, and the user/character/open tag after the title.
For example: [Plot] The Way Out [Whers] would be a semi-open plot thread that only allows wherhandlers or whers to participate. [Fate] Bad Luck Abounds [Fartoo] would be a Fate-type thread (requesting random admin prompt) that will only involve the original poster and Fartoo. I Think I'm Cool [Open] would be an open thread allowing anyone in that area to participate, but doesn't have any special thread type.
Thread Types
[Plot]
These threads are site plot-related and posted by staff; these are usually open to anyone who has a reasonable excuse to be around, but are occasionally closed for specific characters only.
[Rumor]
These threads are posted by staff–generally at maintenance–and are usually gossip-related and by default open to all.
[Event]
These threads are posted by staff and are random small, non-plot-related events for characters to participate in. By default these are open to all.
[Hatching]
A special thread type, these are only used for dragon/wher hatchings.
[Touching]
Another special thread type, these are used for dragon egg touchings only.
[Random]
This tag means that at some point, someone may drop in and do something random! Examples of these are things like finding broken firelizard shells, an odd smell, or finding someone's dirty laundry. These can be dropped into posts by any member! They are mini-prompts to help spice up roleplay.
[Fate]
[Fate] tags are a call for an admin to drop something random in on your thread; like [Random] this can be added after the thread has been going for a while.
Examples of things that may happen could include a character being injured/exposed to something that makes them sick, finding something unusual, or running into something or someone from their past! This prompt will likely only have someone drop in once, since these are larger prompts being added.
If there is anything you would like to avoid for your random/fate, please put it in italics and in (parentheses) at the bottom of your first post, so we can accommodate. :) Feel free to ask questions if necessary.
User Tagging
User tagging is a bit more free-form; [Open] is the only thing really set in stone. Other than that, you can tag usernames or character names, so long as they're kept in square brackets to make it clear it's not part of the thread name.