Overlap Effect
Definition
A Community Leverage principle, as defined by Karmic: some of the people who engage in a brand's subreddit also participate in the other subreddits its buyers read, so building an engaged owned community increases the chance that someone familiar with the brand is present in outside conversations.
Context
The Overlap Effect is the strategic application of subreddit overlap: rather than only measuring shared membership between communities, a brand deliberately builds a community whose members overlap with its target subreddits. Its output is Platform Organic Mentions, which the brand never directs.
Relevance to Reddit
The Overlap Effect explains how one owned subreddit can influence discussion across Reddit without the brand posting in those other communities. The more relevant people a brand subreddit engages, the more likely a familiar voice appears in "best [category]" threads and larger niche communities.
