Russia Revolution took place during WWI, which was a complex period for not only the Russia, but also the entire Europe. The most important thing of Russia Revolution was the changing the regime from autocracy to the communism. The revolution also was a key point to the WWI because it pulled the Russia out of the war, which indirectly ended the war. After the war ended, the idea of revolution, socialism and communism spread to the rest of the Europe, but most of the countries accepted democratic rule rather than communism.
After Nicholas II was abdicated, the provisional government, Bolsheviks, and Mensheviks fought for the power. At 1918, Bolshevils took over the government by military force. The Bolshevik government observing Marxist doctrine, abolished private property. At the same time, it allowed peasants to work the land they had seized. The government also nationalized factories in order to restore production.
Before the Bolshevik came to power, the provisional government allowed the universal suffrage, but Bolsheviks limited slates to candidates from the Communist Party. In March 1919, they founded the Third International, also known as Comintern, to promote the communism. After the revolution, Russia was turned totally under the control of communists. However, the revolution also turned Russia into a battled field where disease, hunger, and death prevailed.
As to the WWI, Russia Revolution was definitely a key factor that caused the ending of the war. Bolshevik signed the treaty and left the war at March 1918. It let US entered the war because now it doesn't have to ally with a autocratic country. Fortified by the US, Allies pushed back the Germany all alone the western front and headed toward Germany. Finally, at Nov. 1918, an armistice was signed and the war was ended.
As Lenin expected, Russia Revolution brought up a revolutionary fever around the Europe, especially in the former empire of Germany and Austria-Hungary. Many of the newly independent people of eastern and central Europe supported socialist principle. But the brutal way that the Bolsheviks used during the Russia civil war were totally different than the earlier utopia socialists, and it gave the world a bad impression about the communism. After all, Germany formed a constitutional republic, and most of the nations accepted the democracy rather than communism.