Short URLs are all over the web with many URL shortning services, like tinyurl.com , bit.ly , tr.im and even the wordpress.com blogging service has their own URL shortening service for the blog posts : wp.me. This is a very convenient feature and best suitable for social networking, by keeping messages short and cleaning the mess of long URL’s. This comes with a cost. You cannot know what is the final destination of the shortened URL, where it will take your after resolving. It can be a malicious site with scripts running behind which can do damage to the system or anything. But until today i did not think it was necessary. I just got a scrap in Orkut containing a shortened URL which was suspicious as it was sent to 246 people. I wanted to see what’s behind it without clicking it.
Googling got me a good solution. The LongURL service and the LongURL Mobile Expander plugin for firefox. This is a very helpful plugin. When installed and enabled, if you take the cursor over any shortened url it would automatically resolve it ans show you the redirected original page link on a small popup. The small popup also contains a more link clicking on which takes you to the LongURL site and provides details about the shortened url, the elongated resolved url and the number of redirects, and a screenshot of the redirected original site. The plugin uses the LongURL service to expand the URLs and making it more convenient to resolve the URLs. If you don’t want to install the plugin you can still visit the page http://longurl.org/expand and manually paste the url to be elongated.
The good thing of the plugin is that it does not attempt to expand all the URLs you point and only attempts to resolve those which start with the domain of some URL shortening service. So pointing to some URL having the URL shortening service domain will be resolved by the plugin. Note that it may take some time expanding the URL by the plugin, you need to keep the cursor on the link for the plugin to work on that URL and get you the result.
Download
Plugin Name : LongURL Mobile Expander
To install the plugin visit: https://addons.mozilla.org/en-US/firefox/addon/8636/
URL resolving Web Service : http://longurl.org/
Phoxis 
Hi Phoxis =)
Thanks for posting this, what a useful plugin to have.
After you know where the link will take you, how then do you know if the site is potentially bad? What does the content type mean?
I saw there is a ‘preview’ tinyurl you can make on Tinyurl, will it do the same?
The content type means what is it in the link, like if it points to a webpage having HTML and encoded with UTF-8 char set then it “text/html; charset=UTF-8” . If the link directly points to some pdf file then it will show: “application/pdf” , if it directly links to some image it shows its format : “image/gif” etc.
I do not know how they generate the preview, but they should generate a preview of any other links you provide as i have seen. Else if the link content preview cannot be generated then they will tell that it cannot be generated.
To know if the site is a bad one or good one, it is difficult to tell. But atleast you could get a view at the original domain site. For example if the original link is from some site you can trust, or you know then you can be sure the link is good. Else if the link points to some site with strange name or domain you have never heard then you can predict what it could be. This part is actually difficult and depends on your experience.
Hi Phoxis, like you say it’s difficult to tell and depends on your experience…(I don’t have much computer experience obviously) but at least I now have more information available than I did! –Thank you =)
if the link points to wordpress.com or such sites you can trust then you can atleast know that they are not bad , atleast.
thank you for this, phoxis – these shortened urls do scare me to death. Huge thank you.
it was very good to know that this helped you. thanks for the feedback