This answer can be found on netboot.me's help page:
netboot.me is a service that allows you to boot nearly any operating system or tool on any computer with a wired internet connection - without having to know ahead of time what tools you need. Once you can netboot.me, you never need to update your tools again!
netboot.me works through the magic of netbooting. There are a number of ways to boot a computer with netboot.me. The simplest is to download a bootable image and burn it to a CD, USB memory stick, or floppy disk. Boot off it on any networked computer, and it will automatically fetch the latest boot options from netboot.me and let you choose from dozens of installation, recovery, testing, portable desktop and other tools. You can also start netboot.me from any computer running gPXE, or from any netbootable computer with some simple tweaks to your DHCP server.
Why use netboot.me instead of rolling your own PXE server? Well, allow me to borrow from netboot.me's Help page again to answer that question:
netboot.me is useful in a number of situations. You can use it as an installer for any number of operating systems and distros, as a rescue disk for a wide variety of setups, as a testing and diagnostic utility for memory, disk, CPU and other components, or even as an instant desktop environment!
The most important advantage of netboot.me is that you don't have to plan ahead in order to take advantage of it. Often, you don't know you're going to need a diagnostic tool until you do - at which point it may be too late to download it! You can download the netboot.me bootloader once, keep it with you when you might need it, and never have to worry about updates again.
Another advantage of netboot.me is for performing OS installations. When you download a distribution of Linux or another OSS operating system, much of the software on it is already obsolete, requiring you to upgrade it as soon as you finish installing. With netboot installations, however, the downloaded packages are always the latest, eliminating the need for an update and reducing the total amount you have to download.
Also, check out this cool video that describes netboot.me in video form. I like the girl's accent. Currently, there are quite a few options available for netbootable installers from netbook.me. They are:
Debian (both 5.0 and testing, for both x86 and amd64 architectures)
Fedora 11 (for both x86 and amd64 architectures)
OpenSUSE 11.1 (for both x86 and amd64 architectures)
Ubuntu 9.04 and 9.10 (for both x86 and amd64 architectures)
FreeBSD 7.2 (for both x86 and amd64 architectures)
Micro Core Linux 2.2 (an even smaller version of Tiny Core)
This project reminds me of a cool remix of Billix, though the projects are not related. If you have a fast Internet connection and love installing different distributions of Linux, this would be an excellent addition to your collection. You can even create your own TFTP server to run netboot.me -- how cool is that? Either way, it's a way to boot Linux (as well as several diagnostic utilities) with a minimum of effort!
Visit zootlinux.blogspot.com for more cool stuff!