This article on RWW about MashLogic suggests one more tempting possibility for Europeana to distribute itself more widely and get itself integrated web-wide, for those users in love with culture (in the widest sense). MashLogic is a Firefox extension that tries to create links between the page you're looking at and resources that you've chosen, built on web services and soon to become open to developers and partners. Some sort of semantic processing is presumably at the heart of it, and it sounds as though you can effectively help to teach it. Evidently it's in a similar space to Adaptive Blue, amongst others, but offering considerable scope for the user to tailor their experience and for content owners (like Europeana) to hook into it.
I guess people are much more likely to install a plugin that can do the same for a variety of providers in preference to one that's only good for one. So if Euroepana can piggyback on something like this, its appeal could made much broader.