Shortened URLs, such as TinyURL and Bit.ly, are more and more prevalent these days with the increased link-sharing on Twitter and other social media services. But did you know that clicking on a shortened URL can be dangerous?

You can’t tell where a shortened URL is pointing. According to Daily Blog Tips, that shortened URL could point you to a web site that tries to install malware on your system as soon as you visit it, or even get into your Gmail account and mess with all your contacts. Whoa!

If you know and trust the source of the shortened URL, it’s safe to click. But if you aren’t sure of the source, be safe and try one of these tools to “unshorten” those little URLs.

• Sucuri.net: Shows the full URL and tells you if it’s safe.
• LongURL: Expands URLs via Firefox add-on or Greasemonkey script.
• Untiny: Check URLs right from your browser’s address bar.