Just wondered if people think it's useful to set up some guidelines for how to best make use of this opportunity to promote your work?

My suggestions are:

Keep it relatively simple.
Name what you're wanting to promote; new book, award-winning story, other competition win, magazine acceptance, book launch, reading at public venue, signing at book shop or other venue, talks about your writing/work, theatre event, radio drama, screen drama, performance poetry event, etc etc...workshop in related areas, I could go on.
Cost of event/book/etc if applicable
How to buy/attend/etc- including URL if linking to Amazon etc
Short biog to let readers know about you and your writing.
Quick flavour of book/etc you're promoting- genre, any review snippets you have, etc

Anyone think of anything else?

Well, going by other groups i belong to, i'd limit the number of posts a member can post per day/week as in some groups i've seen, elsewhere, some writers just put up post after post after post, one after the other.

Yes, very good point. Hmm..will chat to David about this- we want it to be a useful forum for writers, not overrun in a spammy way, obviously. Thanks for that.