Spear Phishing
Spear-phishing attempts target and email specific people and organizations. The hackers and spammers attempt to learn information about you so that when they send you an email, it seems as if it comes from somebody you know, whether it be a friend or familiar business. Spear phishing isn't as common as general phishing attempts because they are much more time consuming to make, but spear phishing attempts are often much harder to detect because it is often addressed directly to you, seems to come from a trusted person, and can often bypass traditional security defenses.
Spammers who send spear phishing emails often use social media sites to learn as much about you as they can. If your information is made public, spammers can look through your recent posts and friends list. Make sure you keep your information private and don't accept friend requests from people that you don't know. If you receive a suspicious email from a friend requesting personal information, you can always contact the person to make sure the email is legitimate.