It can be easy to masquerade a web site as belonging to a reputable company when it does not. Internet domain names are allocated on a relatively arbitrary basis-there is no guarantee that, for example, www.lloyds.co.uk points to either Lloyds Bank, or Lloyds of London. In fact, it belongs to an anonymous third party, who is probably holding on to it until one of the other companies offers them enough money to buy it...! [update - it has now been bought by Lloyds Computers].

You can usually check the domain name of the site with a WHOIS search; this looks up the resgistrant's details as logged by the domain registry. For example, for UK addresses, you can use Nominet's WHOIS service.

There are schemes that give you some measure of confidence that the website is bona fide; if it is a secure site, then you can view the certificate for the site, which is signed usually by a trusted agent such as VeriSign (www.verisign.com). Another guide to trust is word-of-mouth: do you know people who have used the site to order goods, or read in the press that the site is trustworthy?