Now Lion Can Be Recovered via Internet
Mac minis and MacBook Airs were introduced with a new function called "Internet Recovery" that allows to download and install OS X Lion even when hard drive on your Mac
With new Macs, it looks like even after hard drive replacement it will be very easy to do a clean install.
Internet Recovery allows you to start the Mac directly from Apple’s Servers. Your memory and hard drive will be tested by the system to make sure that there are no problems with the hardware.
At first Internet Recovery shows only the limited interface where you can select your preferred Wi-Fi network and, if necessary, enter your WPA passphrase. After that it will download and show a Recovery HD image. From this point you will have the same capabilities and functions as in Lion Recovery.
Internet Recovery function is offered only on newly-launched Macs. Existing owners of Macs with blank hard drive first of all have to install Lion from Apple’s USB key or self-made DVD, or reinstall Snow Leopard.