Thailand's lese majeste law - which is the committing an offence against a reigning sovereign - is considered to be one of the harshest in the world.
Those accused of defaming, insulting or threatening the monarchy face prison terms ranging from three to 15 years on each count.
Sriboopeng's trial was conducted behind closed door because 'what he wrote was beyond rude', Bangkok Military Court's chief judge said.
Major General Panomthep Wesaratchanun added that 'even the prosecutor did not want to read them out loud'.
Thailand's citizens supposedly revere King Bhumibol Adulayadejl, 87, as a moral authority who stepped in repeatedly over the years to unify the country - despite not having a formal political role.