Phishing or Spear-Phishing is one of the most successful types of social engineering exploits. It is a technique that uses email and fraudulent web sites to capture your Username and Password.
Criminals send emails that look like they are from a person, institution or business you are familiar with. Included in the email will be links that looks very similar to URLs you are familiar with. If you open the links, you may be presented with a web page that has the same look and feel of one that you are used to. Despite that it looks exactly like the website you are familiar with, it is a fraudulent site that is used to capture your login info as you type it in.