Remember, if the viewer comes but doesn't act, if the viewer reads but does not act, your site has failed. What the readers to a website want is to have better lives. What all humans at all times are looking for is being better off. To this end, stress benefits not features. In other words, say you were selling a listserver.
Features are facts.
Look at your site. Then it's failing. I like to think of a website as like a little gnome sitting inside the computer waiting for someone to come by. Because marketers and designers work on so many projects, whether on or off the Internet, it's very easy to get blase, to let technique dominate real enthusiasm. In this role, they need to go beyond their technical skills and approach the project afresh, seeing it just the way a prospect will see it.