Bit.ly is not responsible for any form of spam! The users are!! The bit.ly service is indeed used to hide bad links in spam mails, as much as all other url shorteners, HOWEVER, IT'S INDISPENSABLE AND NECESSARY TO SAY THAT BIT.LY IS NOT RESPONSIBLE FOR THE WAY THEIR CLIENTS USE THE SERVICE! If you received an e-mail with a bit.ly link that redirected you to malwares sites, the only person to blame is the e-mail sender, who happened to shorten a URL using bit.ly. It's not bit.ly's fault! The same thing applies for all other URL shortener services. WOT already wrote an article about URL shortener services being used in order to hide bad links in e-mails, but PLEASE what everyone must keep in mind is that such services hold no responsibility for the way people use it. I could post a bad shortened link now here myself if I wanted to, redirecting you all to some malwares site, but that would be MY responsability, not bit.ly's! URL shorteners are great and useful, and the fact that it's used for scam purpose only means that we should be even more careful about what we click. Saying Bit.ly is responsible for spam is the same thing as saying Gmail is responsible for spam just because someone is using their gmail account in order to send spam. It's just not true.
In case you are not registered or familiar with the bit.ly service, you should know that they have a firefox plug-in which allows the user to foresee the original link and it's content before you even click it, so in case it's a known malware site or even a suspicious link, you have the option not to visit the site. The plug-in also "foresees" the hidden links from all other URL shortener services. "

URL Shortening Service. Like all services, can redirect to spam/malicious sites. But the site is generally safe, just like all URL Shortening Services.

Some shortened links load a warning first if they were flagged as being dangerous or spammy. "

System is open to abuse, in this test case the domains to blame are eurdoctors.com and 200.58.114.41. Doctor web scan indicates that this particular email redirected me to the named domains. In Dr webs malicious site list, however I don't know if it is a false positive. I am not assuming either.

PS One way to look at the experience is to review the observation made in this link, http://www.mywot.com/en/scorecard/bit.ly/comment-1949142#comment "

Good for shorten long urls. "

This site itself is perfectly harmless to use and was set up with good intentions, but it can be used by scammers to hide their true URLs. WOT is your best protection against these scams. "

this website is good but most of the links to it redirect to bad websites, e. g. phishing "

Preview link by appending + to the bit.ly URL. That is, http://bit.ly/CUjV+ will preview the page http://bit.ly/CUjV

Also, Firefox "bit.ly preview" add-on allows preview of shortened bit.ly URL by showing the full URL and page title if you hover over the link. Also works for some other shortened URLs such as tinyurl.com

To find add-on, search for "bit.ly preview" on https://addons.mozilla.org "

great site "

bit.ty itself it is good, but Spammer and Junk use this too and they are bad. "

Good site for url redirection and also for making long web addresses shorter, for example in Twitter. Be aware that it may be used to hide the real address in spam emails. "