This is a very cool tool which lets people on several different all edit the same document at the same time, with different people's edits appearing in different colors. Great for when multiple OpenSpace participants want to take an integrated set of notes (rather than posting multiple versions that will probably have repetition, or having to edit them together later).
If you click on the "Create new pad" button on the main page, EtherPad will make up a random web address for your pad. But to make it easier to share the web address with others in your session, you can instead make up your own address - for example, you can just type:
...into your web browser and EtherPad will create a pad using that address. (Keeping it short will help avoid confusion over the address.)