I’m not suggesting that you open up your site for anyone to make changes to it but customers using your website will want a certain amount of control of what they see and when they see it. For example:
1) Don’t disable the “back” button.
Websites should be constructed so that users can go to other pages in any order they choose and go back to pages they already viewed by using the browser back button. Don’t confuse users by not allowing this. Websites built entirely with Flash animation are notorious for this.
2) Don’t automatically start audio or video.
Audio and videos can add valuable information for your customers but let them choose to hear or watch them on their schedule. Don’t startle/annoy them by having sound blare out as soon as they get to your site.
3) Pop-up windows.
Pop-up windows can be useful to supply extra information to the customer such as help on how to complete a form or to see a larger picture. But the windows should be hidden until the customer chooses to open them. Avoid using windows that suddenly appear and move across the screen to display advertising or other unasked for information.