Mail Online and the Department for Transport website of the government are among those that have failed to comply with the `cookie law' that has come into effect in the UK in May.
Under the new cookie law, the IT departments of companies in the UK must obtain consent of visitors to their websites before storing their personal information, legal experts say.
Online marketers have for long been using cookies as an easy way to find out exactly what people are looking at online, so that they can tailor advertisements to the taste of the individual consumer.
Failure to comply with the regulations may invite fines up to £500,000, despite a grace period of over one year granted by the government.
Reports, however, say that a month after the deadline for compliance, Mail Online, the most viewed website in the world, had kept its website intact with all its attendant cookies.
Mail Online might be taking users for granted by relying on implied consent rather than seeking direct consent of users, says the report.