To maintain the scroll position after postbacks is important for larger web pages in order to let the user know exactly what is going on. It is good usability and something you would expect in modern web applications.
Instead of SmartNavigation, ASP.NET 2.0 introduced the MaintainScrollPositionOnPostBack property, which does exactly what the name applies. It has a much smaller impact on the output and it is cross-browser compliant. There are three ways of applying the property to a web page.
You can set it programmatically
In the page declaration
Or in the web.config´s <system.web> section.
This feature is an absolute must-have on large web pages built for postback scenarios. The beauty of it is the simplicity and the low impact.