What's the difference?

* User browses on Twitter, clicks link in tweet pointing to t.co, is redirected off to the page where they wanted to go.

* User searches on Google, clicks link in search result pointing to google.com, is redirected off to the page where they wanted to go.

Admittedly it only happens with half of the search results of the first page (I think; it seems to vary), but it's very much the same technique.

If he was not misled by the false "on hover" representation of the link in his address bar, then its possible he means:

1. That Twitter uses a "short link" where Google uses some kind of (I trust) token-secured "open redirect"

or

2. That Google uses a {Javascript, 301, ...} redirect where Twitter uses a {Javascript, 301, ...} redirect.

Depending on what User-agent I sent, I got Twitter to variously return a Javascript or 301 Moved Permanently response. I could only get Google to return a Javascript response to cURL, but I did not try hard, and I would not rule out Google employing different redirect methods, particularly on their search results page. Google is notorious for falling back to different methods depending on the particulars of the client. See:

http://www.stevesouders.com/blog/2010/07/12/velocity-forcing...

So they at least both use the Javascript method. In any event, if you mod out the content of the hyperlink after the domain, and mod out the content of the text based HTTP response (!), which is fair here, then the methods are all equivalent, and all generate the same server diagrams.

In this case, there is not much difference between the browser parsing plaintext in HTTP headers that tells it to go to a different site and the browser parsing plaintext in an HTTP body that tells it to go to a different site once executed in a Javascript engine.

How does the fake link hover work? With Javascript turned off the first time I hover over a link I see the google redirect url but the second time I hover I see the fake url.

<a href="http://www.fakehover.com onclick="window.location='http://www.goto.com/>; I presume.

Explanation here: http://news.ycombinator.com/item?id=4630082

Well that sucks, I stand corrected. I was looking at browser's link hover and hadn't noticed the redirect. I still don't understand why the browser isn't telling me what I'm clicking on, that's bothering me.

It's because Javascript is allowed to override what's in the status bar.

More precisely in this case, it's because Javascript is allowed to override where clicking on a link actually takes.

It does these days actually, but the urls are re-written by javascript only after you click on them. Try a right click.

"Right click - copy link" is what's most annoying about this URL redirection. You don't want to send an URL of 4 lines in an email or IM, so then you have to go visit the link and get the real address from there.

Can't they do something where the HREF is left intact, but an additional onClick is added to track clicks?