You might have heard recently that Yahoo has confirmed that they suffered a security breach and 500,000,000 (that's 1/2 a billion) user accounts were stolen - including names, logins, birthdays and security questions. This affects not only Yahoo, but Flickr and Tumblr as well.
And this actually happened in late 2014! So if you have an account on any of those sites and have not changed your password since then, you've been vulnerable this entire time. That is B.A.D.! So now is the time to change your passwords and security questions on those sites.
What's worse... if you've used those same credentials or security questions on other sites, you're now vulnerable there as well, as hackers always try to re-play stolen credentials on other, more valuable sites (e.g. your bank). So you'll need to change your credentials on those sites as well. (Remember... never ever re-use passwords.)
This is a perfect time to re-read my last post... Manage Those Passwords.