Ashley Madison, a website used to adulterous meet-ups, was hacked into on July, 9th 2015. The private information of aproximately 37 million people was leaked onto the internet allowing anyone to find the users of this website and their information, ruining relationships and tearing apart families as well as causing a large number of suicides.
What this means for you
This means that whenever you give a website information about yourself no matter how "secure" this website supposedly is, that it can be hacked into and your information can be leaked.
How to prevent being hacked
You can prevent being hacked by giving as little information to others on the internet, as well as practicing internet safety.