Goo.gl opened up for everyone, you can find it here, including history and stats!

<<There are many shorteners out there with great features, so some people may wonder whether the world really needs yet another. As we said late last year, we built goo.gl with a focus on quality. With http://goo.gl , every time you shorten a URL, you know it will work, it will work fast, and it will keep working. You also know that when you click a goo.gl shortened URL, you’re protected against malware, phishing and spam using the same industry-leading technology we use in search and other products. Since our initial release, we’ve continued to invest in the core quality of the service:>>

http://googlesocialweb.blogspot.com/2010/09/google-url-shortener-gets-website.html

[edit: fixed domain name --roger]

BTW: I wasn't able to post the message when used goo[dot]gl, the forum blocked it :-(.

Click analytics are public, that's quite interesting. And the QR codes work too.

But I was surprised that if two people shorten the same URL, they get different short URLs. Even if you shorten the same URL more than once, you get different short URLs. A competitor of Google could easily mount a DDOS attack to deplete the googl address space.

No more need for " tinyurl " ? :P

As I understand it, shortening a URL when not logged into an account generates a common short code per URL. When logged into an account, each shortening request generates a unique code. Your previous shortenings are listed and can be reused.

If the codes are made from an alphabet of 62 characters (e.g. a-z,A-Z,0-9) then there are more than 800,000,000,000,000,000 (i.e. 8 * 10^17) ten character codes. That many requests would impact both google and network resources. It would be noticed. It could possibly be traced to the perpetrator.

I do not know what algorithm they are using. It could be that generating many codes from one account would mostly deplete the short code space available to that account, with minimal impact on the code space available to other accounts.

You can also create a link chain from one goo . gl URL to the next goo . gl URL and so on. Just don't know how that could be useful :)

George R:
> When logged into an account ... your previous shortenings
> are listed and can be reused.

True, but once you have a large set of previous shortenings you're not going to notice the old one, and Google doesn't alert you to it.

As you say, ten-character suffixes are more than enough, but I had assumed that people want suffixes to be as short as possible for as long as possible. Why bring forward the need to use longer suffixes?

> No more need for " tinyurl " ?

I think the time for tinyurl is past. Google is likely to be a more reliable long-term URL-shortener.

But there's an underlying problem here. The main use of URL-shortening is for twitter, where there is a limit to message length. But Twitter's new policy is to shorten links themselves with t.co

So if you post a goo gl link to twitter, and someone clicks on it, it will first go to t.co (whether or not twitter displays the t.co URL). The user's browser will then receive a redirect header, and will request the goo gl URL. Google will then send the browser another redirect header, and the browser will request the unshortened URL. There may be further redirects from the target website.

Not the ultimate for efficient browsing.

I don't use URL shorteners myself. They just obfuscate the destination and add an additional point of possible breakage.

Philipp:
> You can also create a link chain from one goo . gl URL
> to the next goo . gl URL and so on.

After a certain number of redirects, your browser will give up and display a "Too many redirects" error message, so there is a limit to how far this can be taken.

Currently goog.gl seems to generate four character codes.
There are more than 14,000,000 of those.
There are more than 900,000,000 five character codes.
There are more than 50,000,000,000 six character codes. This may be more than the number of pages that google indexes.

Roger Browne:
"After a certain number of redirects, your browser will give up and display a 'Too many redirects' error message, so there is a limit to how far this can be taken."

Since they are all known to the goo,gl server, it could redirect you to the last one in the list. Doing this might impact the statistics it records.

Note: I wrote "goo,gl" with a comma because the forum software seems to have a problem when it is spelled with a period. My usage would not have been autolinked.

Obviously, if you want to get short addresses with your OWN domain name, you can use Google Apps' short links application
http://www.google.com/enterprise/marketplace/viewListing?productListingId=5143210+6352879591152674960

when you have bit.ly account, bit.ly does the same: it generates new shortcodes for the same url.