If I tries to shorten the url of http://google.com http://google.com several times, goo.gl always give back different result. I just wonder will goo.gl merge th

If I tries to shorten the url of http://google.com http://google.com several times, goo.gl always give back different result. I just wonder will goo.gl merge theses url together sometime later? This interesting found implies how goo.gl is designed. They prefer writing directly to avoid duplication check and random seek caused by the check. And they though most of the urls are cold so it is not essential to merge them together to keep the hot cache small. Or they assume nobody wants to play the system in this way. :-)