Too many organizations unwittingly give their competitors a free kick by having Web sites that are low on usability and high on annoyance.

Users have a short fuse when they are browsing the Web, according to Theresa Cunnington, senior usability consultant with services firm iFocus.

"It doesn't matter how cool a Web site looks, if users find it impractical they will head to your competitor's site, which is only a click away," Cunnington said.

"Flash animations are an obvious, yet stellar, example of what users hate in a Web site; the skip intro button is the most used button on the Internet.

"Users hate flash because it's a barrier to the site."

Cunnington describes Flash as a classic example of "Jurassic Park Design", that is, designing what you 'can', rather than what you 'should'.

She said Web sites are constantly torn between form and function and as technology changes, new variants on old issues stand out, and new problems emerge.

Head of Comunet's Web site design, Damien Coyle believes design is crucial for an effective Web site.

"You need to represent your corporate image, which should reflect company ideals," Coyle said.

"Not everyone is going to access your site so you need only address the target audience."

The top five Web site quirks that users hate the most, according to iFocus are:

1. Invasive advertising: Cunnington says users widely despise ads that cover content, ads that flash wildly and ads that chew broadband.

2. Re-inventing the wheel: people do not want to have to learn how to use a site before they can browse it, Cunnington said.

3. 'Leap of faith' links: that means disclosing information on content and file size.

4. Attention-deficit Web sites: "Users have a special hatred of flashing icons and banners, because they draw the eye away from what is important and hinder their progress," Cunnington said.

5. War and Peace length: "A common mistake in Web design is to just [convert] a brochure to the Web. But the Web is its own medium, and communication has to change to reach users. Users are known to read 25 percent slower on the screen than on paper, read fewer words and don't like long pages which require scrolling down," she said.

Another problem is site blindness. "We are now seeing right-column blindness, where users do not see information and links down the right hand side of the screen. This occurs because the right hand column has become known for advertising," Cunnington said.

And the cost of making users happy? It is small if addressed early in the Web development lifecycle, she said. "If it costs $1 to make a change on paper, then it costs $10 in code and $100 when the site is up."