I just realised that a site of mine that is aimed at the UK market did not have a META content-language tag set to en-GB. I had used Webmaster Tools to set my preference for UK, but I wonder whether the meta tag makes any difference as well, especially for other search engines than Google, where you don't have the option of specifying your target country? I am guessing it DOES make a difference when you are working in other languages than English but not sure about English variants - anyone got any experience with this?
Not really from what I've seen. If it does, it's pretty minor and would be used in absence of other geo-targeting factors.