The war in Iraq is testing the ability of many websites to cope with record numbers of visitors.
By Mark Ward
BBC News Online technology correspondent
Net users eager for news of the conflict are turning to the web to keep up with the latest developments.
But the flood of visitors is proving too much for some the websites run by news organisations, government departments and branches of the military.
Firms that monitor the responsiveness of websites are already reporting that some are taking much longer than usual to appear.
Keynote Systems, which regularly tests the response times of busy websites, said the responsiveness of BBC News Online suffered during the busy lunchtime period with average download times rising from 0.47 seconds to 1.88 seconds.
ITV News went through a more serious slowdown with average download times ballooning from 5.66 seconds to 15.84 seconds.
As the conflict got under way, some sites such as that run by Arabic satellite TV broadcaster Al Jazeera were only intermittently available.
The website of Britain's The Sun newspaper was also taking a long time to finish loading.
Nic Newman, head of editorial development and technology at BBC News Online, said traffic to the site had already almost tripled and he expected it to grow further.
Similar leaps in visitor numbers have been seen at the Yahoo and MSNBC news sites.
According to Comscore Media Metrix, the top 15 news sites have seen traffic jump by more than 40%.
Mr Newman said many news websites failed to cope with the huge spike of interest on and after September 11 and many have plans in place to ensure they are not caught out again.
"Everyone fell over on September 11," he said.
Traffic to BBC News Online has grown steadily and the site now regularly copes with more traffic than it did on September 11.
The BBC's contingency plans will help it cope with 10 times the usual amount of traffic, said Mr Newman.
It was not just news sites that saw a jump in visitors - US military sites are also getting a lot of traffic.
Keynote said that during its busiest times the US Army site was taking more than 80 seconds to load. For almost 30% of visitors the site simply failed to appear. The website of the US Marine Corps had similar problems.
Sites telling people what to do in the event of a terrorist attack have also struggled to cope with the sudden rush of visitors.
September 11 tested many news sites
According to Keynote the page the UK Home Office has prepared giving advice about what to do in the event of a terrorist attack has been taking almost a minute to download at the busiest times.
The main page of the Foreign and Commonwealth Office website was taking about 90 seconds to load. Anyone visiting the website of No 10 Downing Street had to wait five times as long as usual for the pages to load.
"It was clear from the outset that people would be using the internet as one of their primary information resources throughout any possible conflict," said Andy Didcott, UK boss of Keynote Systems.
"Unfortunately," he added, "it seems that government website managers have failed to make adequate preparation for the well publicised surge in demand."