To ensure that content extension devices support effective navigation in your site, pay attention to the following:

• Give enough information for users to make a decision. The text in the extension device should let users know whether selecting it to see the full text is likely to fulfil their needs. Clear language and labels are more effective than cute, catchy headings.

• Ensure that essential details are not lost. Extension devices make it easy for users to scan for general topics, but hard to dig out specifics. Make sure that essential information that users are likely to be seeking is not hidden in an expandable panel or at the end of a long page.

• Clearly mark content extension devices. Use symbols or links that users are likely to recognise, such as an arrow, a rotating triangle, or plus/minus sign indicators. They should be a reasonable size so that they stand out from the text, and not be fiddly for mobile users to operate.

• Keep page lengths reasonable. Content creators can get carried away when using extension devices and put too much content on 1 long page. Consider whether the information would be better broken up into separate pages.