I'm novice in web servers. We trying to understang, why
we should move to Web Services.

now I can make web service and client, which can call
server and receive answer.

But can server send Notifications to client, if soem
event happened? For example, is it possible to
make "Clock" web service, which will send time update to
interested client? Or client have to connect to server
1000 times a second and ask "is anything new for me?"

Is it possible to implement "push" instead of "pull",
subscribe-publish instead of ask-reply?

thanks