Most current Web development rests on a database model: the contents of each web page and information about each site user is stored in a single large database file and updated constantly. When a user requests a web page the page is created on the spot and filled in with information from the database.
This means that the way in which a web site interacts with its database system is crucial. ASP.NET has the edge here, being designed around a database model, but PHP users can catch up to some extent by using the scripting macros and shortcuts built into authoring programs like DreamWeaver.
One definite advantage of ASP is that it supports the use of Microsoft Access database tables, so that a web designer can use the full power of the user-friendly Access program on their own PC to create and modify their web database files, including entry forms and formatted reports, while PHP users are limited to less friendly SQL-based data interfaces.