Short summary - Gorbachev favored nuclear disarmament, a policy of free speech / free criticism of Soviet policy called "Glasnost", and a greater amount of freedom to the Soviet republics - which resulted in Latvia and Lithuania (or however the Nords spell those) declaring independence.
Modern-day Russian cartoonists like to compare Gorby and Obama because... I honestly have no idea why. Because both like to praise democratic ideals? Because predicting the collapse of the United States is back in fashion?