I think Wiki-en has got off very lightly, as far as legal problems and defamation issues is concerned. I see that Alexa now makes WP #46 of English sites on the Web. There will come a point when not having serious assets is not an adequate defence against the litigious. (I'm not saying WP doesn't have other lines of defence, but 'not worth suing' may not last forever as the _first_ of those.)
Charles
PS IANAL, all that ...