e.g. imagine (this isnt the real problem but it's v similar) I'm legally required to provide a 'family-safe' search engine. I'd like to permit (or turn a blind eye to) third parties supplying, or users using, plugins that I legally can't supply.
The third party plugins would be downloaded by the site user & I'd have nothing to do with it but the users page then show results I'd perhaps previously been required to hide, or it would mix in results from a third party non-safe search engine. I need to use a technology that assists that architecture while covering my ass and allowing me to deny everything. Nothing on my server can be touched obviously only the users browser.
Disregarding the legal etc issues which are irrelevant to this site what would work? should I build the site in AIR? or HTML + javascript? I have limited experience of these things though I imagine I could hire someone if it was difficult