What happened:
A small group of high school students (or recent graduates) seized hundreds of celebrity Twitter accounts and caused them to issue identical tweets.
Twitter employees were tricked into giving the hackers logon credentials to a customer service application.
What does it mean to you?
Your people continue to be your weakest link.
While security training is crucial (and including social engineering in your penetration testing), automated controls that prevent common errors (such as MFA, behavior-sensitive SIEM, DLP, and automatic segmentation) are critical protections against common errors.