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Two people were murdered in Mexico for their tweets. The pair is thought to have been killed by a drug cartel in Nuevo Laredo after using Twitter to disparage the gang.

The man and woman were found hanging from a pedestrian footbridge on Wednesday, and appeared to have been tortured before being killed. Notes were attached the bodies, reading This happens for... denouncing and were signed with the letter Z.

The Z likely stands for Los Zetas, a powerful drug cartel founded by former Mexican Army special forces troops. The Zetas control large parts of the Michoacán and Tamaulipas provinces and have labelled bodies and kidnap victims with Z in the past.

Many media outlets in Mexico fear the wrath of the cartels and don't fully report on drug gang violence. This has caused bloggers to take up the helm, often at their own peril. While the most recent murders marked the first time that anyone has been killed over a tweet in Mexico, a number of bloggers have been threatened and reporters killed.

Twitter is becoming an increasingly weighty social experiment. It is used by the White House and has brought down politicians, such as Anthony Weiner. It has organized mass movements, such as in Iran's Green Revolution.

On Tuesday, during an intense gun battle between insurgents and police in Kabul, Afghanistan, a Twitter-battle erupted between the Taliban and the NATO-lead International Security Assistance Force.

Even Mexico's President Felipe Calderon himself uses Twitter as a means of communication, and often tweets congratulations and official statements after state police make important drug busts.

The Mexican government has begun to take Twitter very seriously, especially after an August 25 prank-gone-wrong. Two users posted false reports that a drug cartel was attacking an elementary school in Veracruz, sparking a very real panic, as well as 24 car accidents, in the city. The pair has been arrested and charged with terrorism and sabotage, and they could face up to 30 years in prison.

The results of the platform's popularity are sometimes violent and deadly. In the United States, an online argument between two friends in New York City ended tragically, with one shooting the other to death in Harlem.

Apparently in a fight over a girl, the Kwame Dancy and Jameg Blake exchanged a number of angry tweets before Blake shot Dancy with a shotgun in December 2009.

That's not a reason to shoot somebody, Dancy's mother, Madeline Smith, told reporters. That's crazy. I don't know what's going on with that Twitter thing.

They were good friends, that's the sad part about it, Smith told The Daily News. Obviously, I didn't know him like I thought I did. I just want to ask him. 'Why? How could you?'