Mar 04 1999: Three out of a surveyed one hundred web sites are adequately servicing their visitors, the other ninety seven excluding or annoying valuable potential clients.   A new survey from Shelley Taylor & Associates reveals that corporate web sites have a far too narrow focus on one particular type of visitor to their site, such as a potential investor or business client, to the exclusion of other equally valuable visitors.   Although companies are realising the importance of a web site, few have any clear idea as to what a web site can and should do.   Most companies are using their web site for humdrum tasks and pay little attention to the value of content on site and the ease with which one should be able to access information and navigate about the site. As a result, visitors get irritated and leave with a bad impression of the company.   Other companies are far too ambitious and overburden the site with the latest graphics and animations, to the extent that a visitor has to download software before the site can even be viewed. Of the one hundred sites surveyed, only three, namely AT&T, Bell Atlantic and Sun Microsystems, managed to serve their customers, investors and potential clients alike.   It is evident that although companies are dedicated to the Internet as a medium, they would greatly benefit by commiting part of their web site budget to the understanding of what a well designed web site should and can do.