"How Apple and Amazon Security Flaws Led to My Epic Hacking" from Wired writer Mat Honan detailing how hackers were able to delete his entire Google Account, take over his Twitter account, and remotely erase his iPhone, iPad, and MacBook. It's important to read the whole thing - on the last page, he explains why you should not enable the Find my Mac feature in iCloud.
It's enough to scare any sensible person into seeking ways to better protect themselves online. Several websites have made suggestions for doing so including this one from Lifehacker.
One important step is to enable two-factor authentication in both your Google Account and Facebook. Enabling this will require you to enter a code sent to your phone via text message before you can access these accounts on an unfamiliar computer. Thus, even if a hacker is able to change your Gmail account's password, they still won't be able to access it without obtaining the code sent to your phone. There is a special procedure for authenticating on certain types of devices so be sure to follow the directions carefully.
Apple responded, "Apple takes customer privacy seriously and requires multiple forms of verification before resetting an Apple ID password, in this particular case, the customer’s data was compromised by a person who had acquired personal information about the customer. In addition, we found that our own internal policies were not followed completely. We are reviewing all of our processes for resetting account passwords to ensure our customers’ data is protected."