ASP.NET is a technology for creating dynamic Web applications. It is part of the .NET Framework; you can write ASP.NET applications in most .NET compatible languages, including Visual Basic, C#, J# and JScript. ASP.NET pages (Web Forms) are compiled, providing better performance than with scripting languages.
Web Forms allow you to build powerful forms-based Web pages. When building these pages, you can use ASP.NET server controls to create common UI elements, and program them for common tasks. These controls allow you to rapidly build a Web Form out of reusable built-in or custom components, simplifying the code of a page.
ASP.NET provides a programming model, and infrastructure, to make creating scalable, secure and stable applications faster, and easier than with previous Web technologies