Enhanced User Experience not only provides an inviting look and feel to your website but also uses Asynchronous JavaScript and XML or commonly referred to as Ajax that helps web based pages to be closer desktop applications making the user experience richer and more intuitive.
Interactivity includes adding a user friendly Search to your website to navigate through heaps of content or having a Blog for user participation which is now a very popular technique to draw huge crowds to your website
Scalability through use of CSS which has gained rapid popularity and makes sites scalable and easy to change and build on further.
