ud.coop is short for uniteddiversity.coop
You can use:
chat.ud.coop to quickly get to chat.uniteddiversity.coop
office.ud.coop --> office.uniteddiversity.coop
projects.ud.coop --> projects.uniteddiversity.coop
etc
If you have access to our shared server you can also login to create custom shortlinks like ud.coop/opencoops or ud.coop/ukmediacoops.