This would be a great way for guild members in different time zones to communicate, build a sense of community, and cooperate.

I'm envisioning an additional tab in the Spiral Uplink. Anyone who is Member or higher can make a post. All posts expire in a few days unless removed earlier by the poster or GM. Posts are short--Twitter length perhaps. The post has a button on the end to send a mail to the poster.
In my guild it would probably look something like:

CLOUD NINE COMMUNICATIONS

• 11/16 Cheshireccat Looking to do a SL Wednesday night, 8p GMT -5. Who's interested?[Mail Reply]
• 11/16 Knight5 If anyone sees a pair of Shadow Dragon Wings on sale, grab them [Mail Reply]
  and send me a mail?
• 11/14 Cheshireccat Please welcome our newest member: Knight5! [Mail Reply]
• 11/13 Knight4 Hi! :D [Mail Reply]
• 11/11 Knight2 I need an AP recipe--anyone have one? [Mail Reply]
• 11/11 Knight3 What is a good place to farm 4* orbs? [Mail Reply]
• 11/10 Knight4 I keep dying in Heart of Ice--what gear do you guys use? [Mail Reply]

This idea came about when I was thinking that it's hard to communicate with guild members. There are some who play regularly that I've never spoken to. If we could leave messages and help each other out like this, it would make the guild more relevant--and the more people talk, the more friends they'll have, the more they'll play (hint hint ;)

--Cheshireccat