What are the Differences between asp.net 1.0, asp.net 1.1 and asp.net 2.0

Asp.net 1.0 & 1.1 version
In these Asp.net versions IIS should be installed by user.  
Asp.net 2.0 version
In this version IIS comes along with dotnet installation no need to install separately and in Asp.net 2.0 many new features has came into picture like partial classes, master pages, skins and themes, roles and membership profiles, Generics and many new controls etc. I will explain each feature clearly. Main purpose of Asp.net 2.0 is used to increase productivity, use same controls for all types of devices, faster and better web application.

Check below table for Asp.net 2.0 new features.
Asp.net 2.0
Master Pages
In Asp.net 2.0 we have feature called Master Pages by using this feature we can apply consistent look and feel for all the pages in website without writing same code on multiple pages.
Asp.net 2.0 introduces new feature called Themes or skins by using this feature we can customize look and feel of website and apply styles to controls, pages. 
Web Parts
In Asp.net 2.0, Web parts can provide a consistent look for a website and allow user to customize style and content.
Navigation Controls
Asp.net 2.0 provides built in navigation controls those are
       Dynamic HTML Controls
Login Controls
Asp.net 2.0 provides new login controls to help create and manage user accounts without writing any code. Different type of login controls are available those are
      Login Control-which provides login functionality
     Login Status- This control is used to know the login status of user
     Login Name- This control is used to know the name of logged in user
     CreateUser Wizard- This wizard is used to create new user accounts
     Password Recovery- This control is used to return forgot password.
Roles and Personalization
ASP.NET 2.0 has personalization features for storing user details. This provides an easy way to customize user (and user group) properties.
Data Access
Many Websites are data driven using databases or XML files as data sources.
Reaching people with different languages is important if you want to reach a larger audience.
ASP.NET 2.0 has improved support for multiple languages.
Image Controls
Asp.net 2.0 has new controls to handle images
       Image Map Control-Image MAP Control
 Dynamic Image Control- image support for different browsers
Automatic Compilation
ASP.NET 2.0 provides automatic compilation. All files within a directory will be compiled on the first run, including support for WSDL, and XSD files.
Compiled Deployment and Source Protection
ASP.NET 2.0 also provides pre-compilation. An entire web site can be pre-compiled. This provides an easy way to deploy (upload to a server) compiled applications, and because only compiled files are deployed, the source code is protected.
New Server Controls
Aso.net 2.0 has introduced many new server controls like Gridview, Detailsview, FileUpload etc