My networking lunch
Once you spend a meaningful amount of time in a particular community, you become familiar with (and even friends with) most of the key players. Naturally, there are clicks, allegiances, and rivalries, but be mindful of the temptation to use gossip as a way of creating a quick conspiratorial bond with your present company. It may produce a sense of familiarity in the moment, but it speaks poorly of the gossiper's integrity.
Listen to yourself when you start a sentence with, "Confidentially," or "I really shouldn't tell you this but…" or "Just between you and me…". If you finish the comment with words you wouldn't repeat in the presence of the person you've just described, you may find that the only reputation you've called into question is your own.