Hi, I've been approached to build a "private, invite only" comunity website. I've done one of these before which is succesfully hidden from search engines,bots and spiders using Phpbb, but I (and the client) would like more features, kind of like a mini-social network. I'm thinking Wordpress with the buddypress plug-in. Can this be hidden like i hid phpbb? ie robots no-follow, disalow spiders and bots?

Any website can be hidden from search engines. Just set it up in the robots.txt file like you said? You just have to make your own robots.txt file and upload it to the root

Buddypress allows you to prevent any page being seen before login, it doesn't, from memory, have a very good way of handling invite only memberships - registration is either on or off - you'd have to build (or get built for you) a plugin that handles the invite mechanism. I can put you in touch with an ace BP Plugin Developer if you need such a skillset

Thanks guys