Hiding your identity on the internet may well seem to be a good thing, particularly if you are in a country where there is a lot of control. Before downloading such a piece of software and blithely installing it, all users should be extremely careful about what they are doing.

The technical issues are not quite as simple as they may appear to be, and anybody wanting to hide should be extremely careful. For example, it must be remembered that while you are downloading a browser that may give you anonymity, you are not anonymous. You will presumably be using Internet Explorer, Netscape or one of the other browsers. Your internet service provider (ISP) may have a record of that. Once you start browsing, you will be getting cookies, making bookmarks, and creating history files and caches of what you do.

Most of the browsers that give you anonymity either do so in a partial way or ask you to pay for the 'complete' package. Such a package usually will encrypt the bookmarks, the history files and may even erase the cookies. It is highly unlikely that the average user is going to know enough about the technology not to leave some trace on the hard disk.

What this means is that naive users thinking they are being safe may download a browser that will give them anonymity, but that fact will be logged by the ISP. The police could ask for the records of the ISP and they would then know the identity of that person.

If this sounds a bit like the actions of a police state, we would all do well to remember that we support the hunting down and capturing of paedophiles, criminals, terrorists and others. When we disseminate software that allows people to be anonymous, we usually do not ask why they want it.

However, there are other problems here. Just because a small company in California or Karachi says its product will make you anonymous, it does not necessarily follow that it really works. Some of these products make you anonymous to the websites you visit, but not to your ISP.

Perhaps the most important thing of all to consider is the trail. Computers today leave all kinds of data on the disk that gives away what you do. Talk to any forensic computer expert - people who examine computers for legal reasons - and you will see that it can be almost impossible to hide what you do. The greatest difficulty of all is that you would have to have the tools to hide things and the very fact of having such tools would be a giveaway.

This is admittedly an extremely dark view of the world, but most people who know anything about computer security - and that is what this is all about - are usually quite seriously paranoid and think of all the possibilities. If they did not, they would not survive.

There are also proxy servers that will hide your identity or let you access sites that are blocked. There is a potential danger here in that these sites often have a strong political agenda, with financial backing from certain political groups.

It is a sad reality that the technology available to Chinese, Iranian or other nationals wanting to get around government restrictions is the same technology that serious criminals use. Ultimately, of course, it is a choice on the part of the provider and the user.

There is a lesson to be learnt: governments are notoriously slow at grasping what is going on. Neither the Chinese nor the US government can really control the flow of information, no matter what its purpose.

Good or bad, there will always be underground networks distributing a variety of solutions. However, you must be very careful about using them.