One of the most important impacts of the First World War was the end of the Tsarist regime and the Bolshevik popularly-supported coup that led to the creation of the USSR- with all the historical implications that had.
Arguably, Russia's reaction to Austria's threats to Serbia was a major reason why war broke out in August 1914. "Slavs united" has been a force in Russian policy for quite a while (Kosova in 1999 for example).
Unlike the Western Front, the Eastern Front was a war of movement, with advances and retreat, going over much the same ground as in the Second World War.
Russia lost this part of the war- mainly because it was badly organised. Nicholas II (and later the Provisional Government) ended up between a rock and hard place with regards to continuing the war. Neither decision would improve things- a true dilemma.
Ultimately the Bolsheviks ended the war, the Germans moved their troops and launched their offensive- but the Americans were there. The decision of the Provisional Government to continue the war was, probably, the right one.
But, to honest, it shouldn't have had to be made. The Tsarist regime should have reformed earlier. Their error was to all our cost.