Question: I am displaying calendar using calendar control.

Each date is displayed as Link button.

But i want only last 30 days(dates) from current date, to be enabled for client click. on those days i will write some code on SelectionChanged event. But goal is other dates must be disabled for click.

They should not have link button.

Answer: 
Because POP3 does not need as much storage on the server side. And because it is more simple and easy to implement.
Many email services (such as those provided by ISPs) only offer a limited size mailbox. This makes it necessary to download your messages to your computer to be able to store the large number of emails that are common these days.