How much did they understand?
There is a recent post at Seforim which among many interesting topics, discusses some opinions as to “How much effort should people put into learning?,” or maybe more appropriately, “How much effort do people put into learning?” In medieval Ashkenaz, more than one teacher complained about both their students and the general level of learning.  Two interesting related questions are “How much did people know?”, or “How much did people understand of what they were learning?” On Berachot 6b there is an interesting cluster of Amoraic statements:
R. Zera says: The merit of attending a lecture lies in the running. Abaye says: The merit of attending the Kallah sessions lies in the crush. Raba says: The merit of repeating a tradition lies in [improving] the understanding of it. R. Papa says: The merit of attending a house of mourning lies in the silence observed. Mar Zutra says: The merit of a fast day lies in the charity dispensed. R. Shesheth says: The merit of a funeral oration lies in raising the voice. R. Ashi says: The merit of attending a wedding lies in the words [of congratulation addressed to the bride and bridegroom].
The first three statements directly concern learning, but what is also clear is that the origins of the merit or reward described in the first two statements has nothing to do with any type of comprehension, “running” and “the crush”. This is even more surprising being that all of these statements describe the attendance of sages at the pirka and kallah. Rashi’s commentary on the first statement makes clear why, in his opinion the merit or reward is for running and not comprehension, most people couldn’t fully understand what was being taught so the reward was for the performance itself, not the actual understanding of what was being taught. (עיקר קבול שכר הבריות הרצים לשמוע דרשה מפי חכם – היא שכר המרוצה, שהרי רובם אינם מבינים להעמיד גרסא ולומר שמועה מפי רבן לאחר זמן שיקבלו שכר למוד ).
In a Jewish context, the performative and social aspect of learning has been described by Sameul Heilman in his The People of the Book. Returning to the post at Seforim, maybe the ubiquity of the Artscroll Talmud, and the “Artscroll phenomenon” in general, signifies a paradigm shift in Talmud study. While in the past some people were exposed to the aggadot of the Talmud through such works as Ein Yaakov, or such compilations such as Hok le-Yisrael (update: which doesn’t only contain aggadic selections from the Talmud), it is my unscientific guess, which could be wrong and shouldn’t be based on generalizations, that many Jews never saw a page of Talmud, and if they did, they didn’t understand much of what they read. Maybe the modern parallel for public events which involve lots of running and crushing is the SOY Seforim Sale-תבב”א.
 See Ephraim Kanarfogel, Jewish Education and Society in the Middle Ages, pp. 171-172 n.49 for a list of sources.
 I. Gafni, Yehudei Bavel be-Tekufat ha-Talmud, p. 209.
 I would also include similar undertaking in Hebrew such as Hevruta.
 Marjorie Lehman is currently completing a book on Ein Yaakov which will enrich this discussion.