Account security and other related stuff is of very importance which many overlook. Recently Mat Honan got all his most important accounts hacked without the hackers even trying to guess his password once. Mat Honan, for reference, is a writer at Wired.com and also used to write for Gizmodo.com, both are very big sites.
Hackers were able to gain access to his Google, Twitter, Apple and Amazon account all within a few hours. And all they wanted was to get hold of his three letter Twitter username. However in the process they also burnt everything their path. Mat had both his Macbook and iPhone wiped, both of which contained a year's worth of his new daughters pictures - now you can imagine how upsetting that might be for him.
Now the process the hackers used isn't complicated at all, it just takes some time and research. All the info they gained was available publicly and information which Amazon consider to be worthless, like the last four digits of your credit card, Apple for some reason unknown to man think is valuable. With this four digit number the hackers were simply able to call up Apple, give the numbers and they were in, as simple as that.
This was a major flaw on Apple's part and just shows how some of their security methods are not secure at all. They even admitted it themselves.
Head over to the article to get a real insider look at it and read the thorough walkthrough of how they hacked Mat Honan - Mat Honan's epic hacking mess
Mat did fault at times and he admits that. For example if he had enabled the two-step verification on his Google account, used different aliases for his emails and not had everything linked together like he had, the hackers would have not been able to get anywhere. They would have been stopped straight away at the two-step verification at Google. So this is a huge lesson to everyone, enable that damn two-step verification on your Google account, it literally takes a minute and you're set.