Re. the removal of the Ulrika thread - can someone in the UK sue a publication in the US for libel? Is there any difference if the publication’s on the internet?
I am not a lawyer. My legal opinion is worth squat. If you get sued, or assaulted, or lose your case, or your money, or your mind, or suffer any form of loss or injury whatsoever, I am not in any way responsible. If you take my advice, it is at your own risk
You must sue them in the counrty the publication is based in, unless they have an office in your country.
Heh, with a disclaimer like that, I can tell you’re from a litigous nation…
Anyway, I swear what you said is the case - even e.g. between different countries in the UK (famous case where Jack Straw’s [Home Secretary at the time] son was caught dealing hash. They couldn’t publish in England, but they did in Scotland). Yet Tuba has said
I don’t think the SDMB has any worries at all. Any lawyers care to help out? Or are you all too paranoid? 
re the OP - absolutley. Liberace sued the Daily Mirror in London in 1959 for daring to suggest that he wasn’t exactly heterosexual - and won! As Bosda says, you have to sue them in a country that has a connection with the newspaper. However, with international business and multimedia ownership this is not too hard. I seem to remember that some libel actions were taken out in the UK, even though the publication was US based because of the perception that libel is easier to prove in the UK.
The Jack Straw case wasn’t anything to do with libel. IIRC it had to do with naming a minor (who might be) charged with a crime. He couldn’t be named in England, where he was or might be charged, but there was no issue about naming him in Scotland, which is a separate legal jurisdiction.
Whether you can bring libel proceedings in the courts of country X depends on the laws of country X. Most countries (that I am familiar with) will allow you to sue if the libel is published in that country. Thus a newspaper which circulates in several countries can be sued in any of them; likewise a broadcaster whose broadcasts are received in several countries can be sued in any of them.
The nationality of the plaintiff is irrelevant, but his residence may be relevant. A plaintiff will sue in the country where he thinks he has the best chance of winning the largest amount. Hypothetically a person resident in England could sue the BBC, based in England, in the courts of Ireland on the basis that the BBC’s broadcasts are received in Ireland. But on the assumption that he is just an ordinary Joe Soap and nobody in Ireland has ever heard of him, the damage done to his reputation in Ireland must be minimal, and the damages equally minimal. So he would sue in England, even if in this particular case he thought Irish libel laws favoured him better.