Nobel laureate Paul Krugman said he likely fell for a phishing scam. Here's how phishing scams work and how to avoid them.

· New York Times columnist Paul Krugman tweeted Wednesday that he received a phone call indicating that hackers downloaded child pornography on his WiFi network.
· Krugman later said he realized that the phone call, which he thought was coming from his "computer security service," was likely a scam.
· The incident appears to...