Build custom pages that mimic standard user interface functionality

• Improve the user experience with the ease of changing field values
• Increase the productivity of your users

Visualforce Inline Editing lets users quickly change field values on a record’s detail page, saving the user from having to access the record’s edit page first. This feature improves the user experience and increases productivity.

There are two forms of inline editing support: the <apex:detail> component has been enhanced to support inline editing, and the <apex:inlineEditingSupport> component has been added, which gives inline editing functionality to several container components.

Here's an example of the latter:

<apex:page standardcontroller="Account">
    <apex:form>
        <apex:detail subject="{!account.Id}" relatedlist="false" inlineedit="true"></apex:detail> 
    </apex:form>
</apex:page>

See the blog post Spring ‘11: The Visualforce Inline Editing Component for a more complex example.