Congratulations are due to Google on its successful flotation last month. It is well deserved. Google's free service enables millions of businesses and individuals to make sense of the internet.

However, the increasing influence search engines have on day-to-day business decisions raises serious questions. Through Google, research is conducted, new contacts are made, and purchasing decisions taken. Now turn this round and consider how Google affects your business, if you have any kind of internet presence.

Common sense says nobody should bet their business on traffic generated by search engines; but if a large proportion of site visitors come via searches, it happens by default. There is another more subtle influence on the web content many of us rely on, which stems from the fact that many web sites have adapted their content to obtain higher search rankings. This practice is understandable, but unfortunate.

The key question is: what checks and controls are there to ensure that the power of search engines is not abused? In 2002 the US Federal Trade Commission wrote to leading search engines warning that paid-for listings should be clearly distinguished from other search results.

Google and other search portals comply with this, but the situation is not straightforward. In particular, the Adsense affiliate scheme means that a large number of web sites include Google-supplied advertisements, generating income both for Google and the web site owner. To fully comply with the FTC requirements, results with this type of ad should be distinguished from other links that do not carry Google advertising, but they are not.

In addition, non-profit and government sites should be ranked equally with commercial ventures. I have no reason to suppose that this is not the case, or that Google directs more traffic to its Adsense affiliates than to others, but as far as I can tell there is nothing to prevent Google from doing so.

The internet tends to move too fast for regulators, but there is a strong case for enforcing a separation of powers, so that those responsible for search results are free from the influence of those who sell advertising or market other products.

In an ideal world, search portals would be run by non-profit organisations with no concern other than to provide us with the best possible data, but it is hard to imagine such ventures having the vigour and quality of the leading commercial sites. There is also an issue of user education. Search engines tend to reward popularity above other criteria, but this is a poor indicator of good information. A knowledge of search techniques and the ability to distinguish good results from bad are essential business skills.