There’s mounting evidence that the popularity of Twitter has hackers and phishers shifting focus to Twitter accounts.

According to researchers at Kaspersky Lab, cybercriminals are trying to sell hacked Twitter usernames and passwords online for hundreds of dollars.

While this is an outgrowth of existing security problems…

[data-stealing malware is] popular because criminals are starting to realize that they can do better than simply swiping credit card numbers. Bestuzhev has seen Gmail accounts for sale on Russian hacker forums, (asking price 2,500 rubles, or $82) RapidShare accounts going for $5 per month, as well as Skype, instant messaging and Facebook credentials being offered.

…Twitter is being singled out because of the premium hackers and phishers can charge for them:

…one Twitter account, with just over 320 followers, was offered at $1,000 in an underground hacker forum. The user’s name was a simple three letter combination that Bestuzhev thought might make it more valuable to criminals.

The answer is to use the same vigilance with Twitter as you currently use with email. Evaluate the link you are about to click on (URL expander plugins for Internet Explorer and Firefox that will show you the extended URLs without you having to click on them), use a strong and unique password, always check that you are at twitter.com before logging in, and select third-party apps with care.