There are various reasons why the March 1917 revolution was successful. There are relatively widespread but not major facts like the discontent of the Russian people which helped the revolution to be successful and one large reason which really made it all happen. Perhaps the best way of explaining this is to look at why the 1905 revolution was not successful and state the changes that occurred since then.
Some of the factors which stirred up revolution in 1917 had also been present in 1905 although of course they were direr in 1917 since they had had more time to be aggravated. .
In 1905, just like in 1917, there were widespread strikes preceding the revolution as the people manifested their discontent with their country's government. These strikes had the power of showing that the Tsar was losing authority over the country and, more importantly, it stopped the country from functioning causing shortages of basic necessities and of arms for the wars in which Russia was involved both in 1905 and 1917. This all generated more and more unrest in various quarters of the country and most of all among the soldiers that were actually fighting in the war, this then led on to add greatly to the success of the revolution. .
The formation of soviets, a factor which had greatly stirred revolution in 1905, also helped the 1917 revolution to be successful because it joined together the opposition against the Tsar and organized it. However after the revolution of 1905 most soviet leaders had been exiled or forced to live abroad.
Setting up a Duma in 1905 also helped that attempt at revolution because it got the people thinking that a new and better system might really be able to replace the Tsar. However in 1905 the concept of Duma's was still somewhat new to the people and the leaders of the Dumas were contented by relatively little, in other words they could be easily bypassed by the Tsar as in fact they were when he issued the October manifesto.
