In March of 2011, South Korea released 3,000 balloons over North Korea to spread news about world uprisings.

It is a well-known fact how oppressive the North Korean regime is and the massive efforts the government undergoes to ensure censorship. North Koreans live in some of the worst conditions in the world and are completely secluded from contact with anyone outside of the country, while South Koreans live with freedom and prosper. 

As the war never technically ended after the Armistice was signed, tensions remain extremely high on the border. Recently in 2010, North Korea fired several artillery shells on the island of Yeonpyeong, which killed two military personnel and South Korean civilians. 

This caused tempers to swell and although it was not formerly stated, the South Koreans responded by released 3,000 balloons, which contained over 3 million leaflets, relaying information to the North Korean people. Inside the balloons were flyers outlining the uprisings that were occurring in Africa and the Middle East against repressive regimes in the hopes it would inspire some popular sentiment against the North Korean government. 

(Source)