Twitter warns against using the same password on multiple sites
In a new post on Twitter's Status blog, Twitter points out that a sudden surge in followers on a few select accounts was due to a large number of insecure passwords being used by regular Twitter users. What's happening is that users are re-using passwords that they've used on other sites, and some of those other sites turn out to have not been secure.
That's the thing; as soon as any of the sites you log in to gets compromised, the email address or username and password associated with it can be tried by the bad guy on various other services. Since most people re-use passwords, there's a high likelihood that they will gain access to your account. From there, who knows what kind of damage they might cause. If you're lucky, you'll notice something's amiss.
This should be a wake-up call for all users who use the exact same password, or a predictable variant at each site they log in to. If you haven't already, right now is as good a time as will ever be to make sure you're using unique passwords for all of your online services. You never know when one of them might get compromised.