Another mod, or Eve, can correct me if I'm wrong on this, but that rule is primarily based around the mention of other SIM games like WP or its sister sites to prevent promoting of other games and/or inviting players offline, which WP can see as predatory and unsafe. Social media's are allowed to allow others to connect with each other, should they become friends. Finding others offsite isn't recommended, but some people do like to keep in touch past WP, lest they end up never logging in or they enjoy the conversations they've had with another person. We have to credit all images used, and as Deviantart is a site most would turn to for art, it is allowed, seeing as it isn't another 1. Roleplaying based site (yes, I know people CAN use it to roleplay, but that wasn't it's primary intention for creation) and 2. A Sim game for others to meet on.
As for what isn't allowed, I'm not a chat mod, or game mod, but it follows the same rules as a forum post per se, in the sense of what isn't allowed and what is.
We are not allowed to discuss other website games, Sim games, or any site that may be a competitor to WP.
We are not allowed to invite others off site in a way that can be seen as predatory.
We are not allowed to EVER invite others off site to get around roleplaying rules as this is strictly seen as very predatory.
We are, from my knowledge, allowed to share Deviantarts, snapchats, instagrams, as ways of keeping connected, especially during a hiatus or when one is leaving the game, though mentioning you are leaving the chat isn't allowed, that would have to be sent through pms. The hosting sites are allowed as its allowed game wide, an example would be when it comes to artwork, and we need a place to upload the pictures to, if that makes sense.
I will not lie, I am not very sure about Skype or Discord, you'd have to ask Eve herself, or Kodiak as they've asked her before. I think it could be seen as inviting people offline, but, again, I'm not sure.
- I just asked Kodiak about Discord and they did say this "Discord is fine to my knowledge as long as you aren't inviting anyone into groups etc"
Again, if any mods or Eve find that I have said something wrong, I apologize and please correct me, but that is from my knowledge. I know you asked for chat especially, but the forums follow the same guidelines, plus or minus a few things (example, you can't roleplay in chat, but forums you can, small things like that).
Fall 
Night 
Hurricane Moon: 
