Complex sentence: Apparently, common townsfolk used to gather at such meeting points, making small talk, and hence the topics they discussed came to be described as "trivial", and hence the word trivia for any information that is of fleeting importantance and of general interest.
Split into simpler sentences: Apparently, common townsfolk used to gather at such meeting points, making small talk, and hence the topics they discussed came to be described as "trivial". Gradually, the word trivia came to be applied for any information that is of fleeting importance and of general interest.