In 1517, Martin Luther was to do something, albeit by accident, that was to change the face of the world as it was then known in Western Europe, and introduce the German Reformation - write the '95 Theses'.
Luther had been troubled for a number of years by his faith and this was made worse when in 1517 John Tetzel was empowered by the pope to sell an indulgence to pay for the restoration of buildings in Rome, primarily St. Peterís. Luther believed that the people of Wittenburg, Saxony, were being conned into believing that they had been forgiven for their sins and that this simply was not happening. This whole episode was symptomatic of what any referred to as the "rotteness" of the Church.
In response to this action by Tetzel, Luther wrote a pamphlet called "The 95 Theses" which was an obvious criticism of indulgences. The pamphlet contained ninety five points that he felt should be argued at an academic level - they were not for general public discussion.
There are two reasons for thinking this:
The pamphlet was written in Latin which was the traditional language of the scholar then and beyond the understanding of most people including the rich and even members of the European royal families some of whom were not literate in their own language let alone Latin !
The pamphlet was not released to the general public to read but it was pinned to the church door in Wittenburg for other scholars to read and to discuss in preparation for a full discussion at a later date. This was the traditional manner for a scholar to bring attention to his work to other academics to allow for a full discussion.
There was nothing revolutionary about what Luther did - it was the standard accepted practice of those academics who attended the university at Wittenburg.
What happened next makes it appear that Luther was a revolutionary but this was not so.
Someone took down the pamphlet and made a copy of it. It would be normal for a number to be made available for all the academic staff at a large university. Someone then had it translated into German and it was printed off for the general public to have greater access to it. When Luther found out what had happened he tried to get back to original copy but to no avail. The "95 Theses" had gone public and was no longer merely a topic for academic staff.
The majority of people could not read or write in 1517 but it was common for a person who could read to do so out in the public domain (such as a market square) if he believed that he had something of interest that others might want to hear. This is how the information in the pamphlet spread within Wittenburg and the surrounding area and many people in Wittenburg clearly identified themselves with what was stated in the pamphlet about indulgences especially as they were the ones who had to pay for them and were very much out of pocket when this happened.
Saxony in 1517 relied heavily on agriculture for its wealth and therefore traders came into the city and left to go to the outlying areas where they lived. It is probable that this is how the thoughts of Luther spread so quickly. Do note that his ideas would not have spread if they had meant nothing to the people in north Germany.
The non-payment of money towards indulgences could potentially save these people a lot of money. The impact of word-of-mouth communication to Luther was huge but difficult for historians to quantify. It is possible that towns were more likely to convert to Lutheranism as more people lived in them and the opportunity was there for communication to spread quickly. Rural areas tended to be much more conservative in general but these areas in north Germany were to support Luther as well as urban areas.
The response of the public to Lutherís work was outside of his control in the sense that once a respected academic was seen to be questioning the stance of the Roman Catholic Church, then it is likely that other less educated people might follow suit. It is unlikely that it would be the other way round!
Lutherís attempt to retrieve that pamphlet prove that he was not setting out to do something drastic or revolutionary. His failure to do so was to have massive consequences for Europe and lead to the Reformation.