"I think you just need to decide that you are content to have every word/post (that doesn't get removed) subject to MN use and further use by any blog, FB or twitter user."
Yes Wotzy you do! No one is trying to pretend otherwise - that's what we explicitly make clear in all our notices - you post on here, it's our liability (not yours) and you share copyright of your posts. We have the right to delete your words and/or use them for MN books and publications. Other people have the right to search your posts, link to them, cut and paste them selectively.
(Though it seems the Daily Mail may not have the right to copy whole extracts at least.)
It's the downside of a public board - the fact that folks can search and quote your nicknames. It's a downside of MN that we may use your words and nickname offline in our books - it's how we pay the bills. It's up to you whether you are happy with that - whether you think we're going to be sensitive to your posts in our books etc. It's up to you whether you can live with being searchable and the risk of a journalist using your words to illustrate their articles.
On the upside - Mn provides for free what only an open board can do - volume, speed, immediacy of answers. Lots of new blood, no heirachy of poster, a democratic open to all spirit.
But whether all that is worth the downside, only you can decide.
Until we've built our private boards, though, that's all we can offer.