Web Role vs Worker Role

Windows Azure currently supports two types of roles:

1.       Web Role

2.       Worker Role

A comparison chart can be as

Web Role	Worker Role
Customized for web application development	Useful for generalized development, performs background processing.
Driven by a UI, involves user interaction and process the request.	Performs background processing
May define a single HTTP/ HTTPS endpoint for communications with external clients.	May define a number of endpoints using HTTP, HTTPS or TCP
Can communicate with other roles in a service via single HTTP endpoint	Can  define internal endpoints for HTTP or TCP

Both web and worker roles can make outbound connections to Internet resources via HTTP or HTTPS and via Microsoft .NET APIs for TCP/IP sockets. All roles may access the Windows Azure storage services via the REST APIs or the Windows Azure Storage Client Library