A question about the term: "asynchronous web service"

What is exactly the meaning of the term "Asynchronous Web Service"?

Does this mean that the Service itself returns immediatly, but the operation continu working on the server side?

Or,

The client starts a new thread which call a SYNCHRONOUS web service, in this way the client does not block until the web service returns

Any thoughts?

[366 byte] By [Guy_Hudaraa] at [2007-11-27 9:01:26]