The BBC News wikiproxy (via every UK geek blog in the world) is, I have to admit, quite cool, as a proof of concept. But as well as wincing at the bandwidth & processor time that it must eat up, I think it is limited in scope - why just Wikipedia references? The promise of a Firefox plugin to the same sounds a lot more exciting - if it could be made adaptable with the Firefox search plugin and all the already-written search engine metadata, so we could add in our own choice search engines (rather than add yet more demand to poor old Wikipedia) it would really bring out the potential of cross-referencability in the browser very nicely.