One can chant the megillah either standing or sitting. If it is chanted by one, or by two, it satisfies the obligation. Places where the custom is to bless, they should bless; not to bless, they should not bless. On Mondays, Thursdays, and Shabbat Minhah, three readers chant. They may neither add nor subtract [from three], and they should not conclude with the prophets. The first and final Torah readers bless [respectively] before and after the reading.
This Mishnah is a window into early rabbinic customs of chanting scripture. Note the relative informality of regulations surrounding the chanting of Megilat Esther compared to the Torah reading. It is permissible to conduct two megillah readings in the same room, even if the sounds mingle. The Talmud states that the custom in question here is whether to add a blessing after the megillah reading; however, all agree that it is necessary to bless before the reading. Regarding the Torah service, it seems that the original custom was for the three passages to be read by three people, with the first reader saying an opening blessing and the final reader saying a closing blessing. This evolved to our current custom, where each reader says a full set of blessings.
In what other ways is the Torah reading treated differently from the chanting of prophetic and other biblical selections? Why?
This Mishnah documents the evolution of chanting customs. How flexible should communities be in adapting the chanting of Bible to suit the needs of their congregation? How does the Mishnah straddle the competing needs for local custom and global standards?
Why do you suppose there were extra blessings added to the Torah reading? Was it to augment the honor of the Torah or the honor of the readers?