Ransomware is a serious problem: rather than harming your data or stealing your identity, ransomware can encrypt your computer or your whole network until you pay a fee. The perpetrators and their accounts are typically overseas and they usually ask for untraceable money, like Bitcoin. Some large companies have been forced to secretly pay the ransom to get their networks back.
Wired magazine said one avenue for infection is compromised ads on trusted websites. So avoiding questionable sites is no longer enough. And to read the article on Wired’s web site, they make you disable ad blockers! You can’t make this up.