Of all the web sites belonging to coaches, consultants and experts that I have reviewed, more than three-quarters shared a very serious marketing blunder: Their potential clients wouldn't understand from their home page precisely what they do. Jargon gets in the way.

Many specialists believe that they need jargon to communicate their expertise. Without it, they'd sound incompetent, they think, and those in their target market who are as specialized as they are wouldn't respect them. My recommendation is not to eliminate jargon, but to include it in the site, with your main emphasis on the business benefits your company provides or the problems your company solves.

For instance, I've done an informal survey to see if business owners understand the jargonistic tag line, "CRM software for small business." Nope! Most aren't even sure what "customer relationship management" really means. But if you write, "Close sales faster and improve customer loyalty through customer relationship management (CRM) software for small business," you'll earn greater comprehension, without alienating those who already know the shorthand.

Don't think this applies to you? Sorry, it does. Nearly everyone in business overestimates - usually greatly overestimates - the extent to which customers understand their jargon.

The other nearly epidemic blunder at sites belonging to coaches, consultants and experts is not explaining clearly and persuasively why someone should use you rather than the competition. What's unique about you? How do you differ from your colleagues? If everyone is qualified and experienced, why should I choose you? With sufficient thought and care, you can add text to your web site that gets potential clients thinking, "This is exactly the person who can help!"

Related to this is the absence at many sites of two powerful tools for credibly distinguishing yourself from the competition: testimonials and expert articles. Testimonials are quotes from clients you've helped, and they should refer to results achieved with your help - not just you being a competent, nice service provider - and be signed with a complete name and business identifier or geographical location. Expert articles engage visitors to your site and show that you know your stuff.

Finally, all coaches, consultants and experts need to have a newsletter to capitalize properly on visits to their web site. This is because people shopping for professional services sometimes decide to buy that very day. More often, they come to your site looking for information rather than to hire someone. If they read a couple of your articles, like them and sign up for your newsletter, you'll have the chance to impress these potential clients repeatedly. Down the line, they're likely to hire you, sometimes without ever returning to your site. But your site set that process in motion.

Marcia Yudkin is the author of Web Site Marketing Makeover and 10 other books. A four-time Webby Awards judge and internationally famous marketing consultant, she critiques web sites and performs web site makeovers for clients. Learn more about her detailed critique sessions on five different kinds of web sites (including sites for consultants and other professionals) at http://www.yudkin.com/websitequiz.htm .