There has always been concern from web uses over the use of cookies, probably largely due to ignorance of what they are and their function.

A cookie is a small file that is placed on your hard drive by a web page. It can store information about you that can then be used by that web site when you return to it. They are in wide use on the web to customise web sites. A good example is the one used by Amazon which allows them to say "Welcome back, Mr ..." when you next go to the site. The site uses the cookie to recognise its customers and thereby saves time completing order forms etc.

An example of how they are used in research is during pop-up surveys, to ensure that repeat visitors do not get hassled by the survey more than once. Seems pretty helpful stuff, so why all the fuss about them?

There may be two main reasons here. Firstly, when they first were used there was lots of bad press over potential hazards and risks of crashing users' hard drives. These fears have proved groundless, but nevertheless the bad feeling has remained.

The second reason is that people instinctively dislike the concept of someone else placing a file on their own machine, particularly if it is done without their knowledge. In these days of openness and honesty on the web, cookies still have a negative image.

If you're worried about your cookies, you can set your browser to reject them, or warn you of them. (You can also look at them or delete them by viewing your Cookies file in the Windows sub directory).

Interestingly though, few people bother too much. In a recent survey we conducted, we found less than a half of one percent of web users had their cookies turned off.

OK, so if you are not too worried about cookies, how about this for something definitely more sinister - web bugs. By their very name they conjure up images of viruses all over your desktop. Again, they are a lot more benign than you would imagine.

A web bug (or beacon as some call them) is a very small, one pixel, transparent and typically invisible image used to monitor your activity. These can either be included in web pages, HTML emails, or even Microsoft Office documents. When you open a document or web page with one in, the image is retrieved from a third-party web server. The key bit of information it retrieves is your machine or IP address. For some users this could indeed reveal your whole name and company address.

By attaching code to place a cookie, information can be logged about you. For example, a completely different site cooperating with the original site in the use of the web bug can then read the cookie when you visit that site and use the information therein.

A particular use of web bugs within HTML emails is that it allows the sender to count how many messages have been opened and who else they have then been forwarded to.

There is likely to be a lot of discussion and controversy over their usage in the forthcoming months based on lack of user consent and/or knowledge. If your company is now using web bugs, ensure your privacy policy is updated accordingly