The .NET Framework is an application (desktop, web, and phone) development platform that provides services for building, deploying.
ASP.NET Web Form is event-driven model, provide hundreds of control and component having events. ASP.NET Web Forms lets you build dynamic, powerful UI-driven sites with data access. It is one of four programming models(ASP.NET MVC, ASP.NET Web Pages, and ASP.NET Single Page Applications).
Web Service is business logic component, which provides functionality via the internet using standard protocols such as HTTP. Web Service uses SOAP(Simple Object Access Protocol) in order to expose the business functionality.
WCF is a combination of NET remoting, MSMQ, Web Service and COM+. WCF = Web Service + Remoting + MSMQ + COM
ASP.NET SignalR is a new library for developing real-time web functionality. SignalR provides bi-directional communication between server and client. Now Servers can push content to connected clients instantly as it becomes available and client can call methods on server. SignalR supports Web Sockets, and for older browsers falls back to other compatible techniques.