Is this link good?

A number of friends have clicked on a bad link, and then unfortunately had something bad happen (some virus/spyware was installed on their computer.) How can you tell if a link is real/good? A few things to keep in mind:

1. Is the link really what it says it is? Put your mouse over the link. For example, the following link says it's going to http://www.m-w.com. However, if you mouse over it and look at the actual link as indicated near the bottom of your browser, it's actually going somewhere else.

http://www.m-w.com

2. Does the link have a domain name you'd trust?

• To figure out the domain name, look at the right-most portion before the first '/' (while reading from left to right.)
  For example, amazon.com is the domain name in this URL: www.amazon.com/gp/goldbox/ref=cs_top_nav_gb27
  
  
• If the domain is unfamiliar, you may not want to go there:
  www.someplacesketchy.net/deals
  
  
• Some links may look like they go somewhere safe, but don't really:
  www.amazon.purchases.com/todaysdeals
  In the above example, purchases.com is the domain name. NOT amazon.com!

If the link looks sketchy, I'd avoid opening it.

3. I've already warned you about redirecting, shortened URLs.

4. Who sent it to you? A stranger, a friend, a trusted company? Emails from strangers are probably SPAM. You may trust a link from a friend, unless their account has been hacked (or they just don't know it's a bad link.)

5. In what context did you receive the link? Was the link sent to you in a Facebook message, an email, instant message, etc that was (1) short (little or no other text), (2) had no context, (3) general, (4) looks like anyone (or a robot) could have sent it to you, or (5) seemed to come out of no where (you haven't spoken to this person in a while)? If so, beware! The message may not have come from who you thought it came from.

Watch where you're going!

Shortened URLs, such as those created by the tinyurl.com, bit.ly, and tiny.cc, have become quite common.
They turn a super long URL such as:

http://www.amazon.com/Peach-Beanbag-Purple/dp/B001I82E5C/ref=sr_1_65?ie=UTF8&m=A1BP9IUW2BQTAE&s=sporting-goods&qid=1247289816&sr=1-65

into a shorter url such as:

http://bit.ly/10FkOL

I'm a bit uncomfortable around them.

Yes, these shortened URLs are nice and convenient. They make super long addresses look a lot nicer, and they’re great for status updates such as on Facebook and Twitter, where you are typically limited to a certain number of characters.

But I feel uncomfortable because I can't see exactly where I'm going. "http://bit.ly/10FkOL" doesn't tell me anything. I have no clue that it's a link to an item on amazon.com. Just as in real life, you wouldn't drive to an unknown or unfamiliar location (it could be in a bad neighborhood!), you also don't want to surf to a bad site, which may lead to bad graphics (at the very least), phishing, or malware injected into your computer... Spammers like to use these shortened URLs, because they can easily bypass SPAM filters. They can also more easily bypass other security features provided by your browser.

What can I do about them?
You can check on the link before you go to it. Many of these URL-shortening sites provide a preview feature. (For example, go to http://preview.tinyurl.com/msezvx instead of http://tinyurl.com/msezvx. You can also go to other sites (like http://longurl.org/), type in a shortened URL, and see where it'll lead to without actually going there.

There are also browser plugins (like this one or this one) that you may use, and when you hover over the link a preview and link to the real site will automatically appear on-screen.

If you are providing a link, just include the entire address or use a regular link like this so that when a user hovers over the link, he can just look at the browser and see where the link will take him. If you are using Twitter, you may not be able to avoid using a shortened URL. Oh well.

My friend sent me the link - can't I just trust my friend?
Your friend is probably more trustworthy than a random unknown source on the internet - you can usually trust your friend.... unless (1) your friend's account was compromised and your friend didn't really send you that message (this has happened to my friends on Facebook and in instant messaging services).. or (2) your friend didn't know what he sent you is a bad site.. or (3) the site providing the URL shortening service was hacked (as has happened before.)

Be careful with shortened URLs - they may be bad sites in disguise!

Update: bit.ly's blog entry about what it does to protect against SPAM and malware. It'll give you warning message if it knows some site is probably a bad site before redirecting you to the actual site. That's a nice addition.