We have an unusual requirement when it comes to developing the BBC website - it carries advertising internationally but not in the UK, and we have to build and design for both these situations simultaneously. The site carries advertising internationally so that UK licence fee payers don't cover international costs. Some content on the site is available in the UK but not internationally - notably certain rights restricted video. Up to now we have had: A UK edition without ads, A UK edition with ads, an international edition with ads and an international edition without ads, all in addition to some content which is visible in the UK but not internationally. Managing all those combinations within our existing design framework had become impractical as well as expensive and, critically, had started to affect our ability to find the best ways of developing the site in the future.
We have an unusual requirement when it comes to developing the BBC website - it carries advertising internationally but not in the UK, and we have to build and design for both these situations simultaneously. The site carries advertising internationally so that UK licence fee payers don't cover international costs. Some content on the site is available in the UK but not internationally - notably certain rights restricted video. Up to now we have had: A UK edition without ads, A UK edition with ads, an international edition with ads and an international edition without ads, all in addition to some content which is visible in the UK but not internationally. Managing all those combinations within our existing design framework had become impractical as well as expensive and, critically, had started to affect our ability to find the best ways of developing the site in the future.
via http://www.bbc.co.uk/faqs/website_changes
There's more info there about how they do it (GeoIP) and some known issues.