The two city EMTs whose racist Twitter rants were recently exposed by The Post are examples of the need to be extremely careful while using social media, Mayor Bloomberg said yesterday.

“I don’t understand why people don’t understand that anything you write, anything you send out is going to be re-tweeted, re- Facebooked, re-this, re-that,” Bloomberg said one day after EMT Lt. Timothy Dluhos was suspended for 30 days without pay as the FDNY probes his postings.

Dluhos — who called Bloomberg “King Heeb” in a tweet — cried like a baby when confronted Friday by The Post. Less than a week earlier, FDNY Commissioner Sal Cassano’s EMT son, Joseph, resigned over his own racist online rants.

Bloomberg offered this Internet-age version of the Golden Rule: “Write down, No. 1, only things you believe, and, No. 2, think about how it would look if somebody else sees it.”