The Gemarah says "The primary reward for hearing a Torah discourse is for running to it" as Rashi explains because most people will not understand it well enough to repeat it. From this Rashi it seems if one does not remember what he learns there is no reward for talmud torah. Is this true in all cases or in the specific case of going and listening to a shuir and not retaining what was learned, however, if a person was an active participant in the learning he will get reward for talmud torah.
Thanks a lot,
Sholom Rose, Baltimore,USA
Rashi does not say that the people will forget what they learned. What he says is that they will not grasp what the Chacham says, in which case they will receive some reward for their efforts, but mainly for their eagerness in running to hear the D'rashah.
As far as forgetting one's learning is concerned, see Pirkei Avos (3:8), which discusses this point. Provided that one has done nothing that the Mishnah warns against, there is no reason why one should lose any reward at all for forgetting.
Kol Tuv,
R. Eliezer Chrysler