This format is a bit different that you will see in examples. The reason I use this is it is easier to pass GET variables attached to the page. The sprintf function makes it easy to format a character array.
You could use the standard three client.println() calls to do that, but bear in mind each call to client.print(), client.println, or client.write() is sent in its own packet.
client.println("GET / HTTP/1.0");
client.println("Host: www.mydomain.com");
client.println();
Why send three packets? The client.write(outBuf) sends all that in one packet. Clean.