Whats the ADO.Net Data Services ?
Whats the advantages it will give me while building an ASP.Net website.
I used to make my JavaScript client side code call a web service and get back a json for Ajax calls on my page.
Is ADO.Net Data Services something which will help me in this scenario, it can simplify returning the data or its talking about something else?
ADO.NET Data Services are a way to expose your data model (Entity Framework and/or Linq2SQL) / database using web services. It gives you the ability for URL querying. It will return the data in XML.
I've not actually tried to parse the result set from ADO.NET Data Services in Javascript but I guess it can be done. It may be easier just to make your own services to access.
In short ADO.Net Data Services is a framework that exposes your data via a web service using a REST interface. You can expose any data source that has an IQueryable provider written for it.
The data can be returned either in AtomPub format or JSON, and the framework provides a method for automatically creating client side proxies that you can use to call the services directly from your web applications.
So... to answer your other questions. Yes, Data Services can make it ridicoulously easy to call your data from the client and consume it using JSON. Since it can expose almost any collection of data, or any backing store (including XML), I think it can help you out a lot.