Sit down and have a look around. There isn't much here yet, as this site is starting from the ground up.
If you are a Horizons player, a former Horizons player, or a prospective player, you are welcome and encouraged to contribute. First, you should learn about the motivation behind this site. Then take a look at the rules. Once you have done that, log in (or log in and register) to start.
If you do not get the registration E-mail, first, check your spam/junk mail. It might be in there. If you find it and the link no longer works, simply request a new password. If you continue to have trouble, drop an E-mail to [nadia at <this-domain--it-has-8-characters-followed-by-dot-com>] and we'll work something out.
The forum is the main place to go -- everyone who is registered (and not banned) can post there.
There is a community wiki to collect and organize information in a more permanent fashion. In past community sites, content for this wiki would have been kept in stickied forum posts. To add and edit articles for the wiki, please place a request in the forums to be given the necessary permissions. I would appreciate a few sentences explaining your motivation and experience. The post will also be used to judge the quality of your writing, so take your time and don't use shorthand like "u", "ur", and "4".
Photos and screenshots can be posted in the gallery. Make sure to read the instructions first!
Talk with other players in the Istaria IRC channel. For those who don't want to install a client, a web portal is available at the above link as well. Sorry, no access for anonymous users. :)