Can you really say what you want online? Across the world, the internet is suddenly facing a onslaught from individuals and organisations fighting back against online material which, they think, is illegal. More and more are trying to prove the internet is not above the law.

For long enough, "netizens" have bragged the internet simply cannot be gagged. One wit, quoted in Wired magazine in 1995, compared the internet's attitude to censorship to its in-built capacity to cope with damage caused by nuclear strikes. "The internet interprets censorship as damage, and routes around it," he said.

But already this month there have been three major attempts to clamp down on what can be published online. The right to completely free speech online has never come under greater attack - not just in the US, but in Europe as well.

The most recent challenge was launched yesterday in a San Francisco court, where Daniel Curzon Brown, a professor of English, is pursuing a lawsuit against the operators of a website. The site in question, teacherreview.com, contains vehement criticism of the professor posted by his students. He says the attacks are "evil" and that he is now "depressed and afraid" because of them.

But it is not just in the US where online freedom of speech is being challenged. Europe is also seeing a rash of court cases where material published online is being challenged under national law.

The Paris-based International League against Racism and Anti-Semitism (LICRA) is taking internet portal Yahoo! to court over Nazi memorabilia being sold on one of the websites it hosts.

Although Yahoo! is not directly responsible for the content, LICRA demanded on Tuesday that Yahoo! take steps to prevent the sales in France, where it is illegal to exhibit or sell objects with racist themes. A hearing has been set for May 15.

Meanwhile, in the UK, internet service providers are still worrying over the repercussions of Dr Lawrence Godfrey's successful action against Demon Internet, which means that in the UK internet service providers can be held liable as publishers for the information stored on their servers, including newsgroup postings and web pages created by subscribers.

Can the internet ride out this onslaught? For now, it can: controversial websites will flee the more heavily regulated countries for servers located abroad, run under more lenient regimes. But the real problems could come if run-of-the-mill e-commerce and information sites decide the risks of being sued are too high in the US or UK, and decide to move elsewhere.

For the UK, the situation could be further complicated by the regulation of investigative powers bill now going through parliament, which would hand the security services sweeping new powers to intercept encrypted communications.

All this could persuade entrepreneurs and service providers to move their servers to less heavily regulated countries, saving themselves the worry of lawsuits over content they do not control.

And, once again, the internet will have neatly routed round the problem - and dealt a hefty blow to the e-economies of the countries they have abandoned.