lucy24 - 12:29 am on May 17, 2013 (gmt 0)
How 'bout this way: The server doesn't know that you said "target = '_blank'". The server only knows that there was a request and, optionally, that the request came with a referer.
It's pretty exactly the same principle as clicking on a fragment link on a page you're already on. (The server can send fragment links, but it doesn't receive them. Information in query strings doesn't count.) The "target = '_blank'" statement is used only by the browser.