The Overlap feature (in Collections, or straight from the search results) shows how much the audiences of 2 to 10 creators overlap. It is based on engagement: for every creator, influData collects the people who commented on their content and compares these commenter sets, a good proxy for the active audience a campaign line-up actually reaches. Prerequisites: all creators must be from the same platform, and every creator's audience report has to be unlocked; the overlap unlocks missing reports automatically for 1 report credit each (already unlocked creators are free, the comparison itself costs nothing). The calculation takes a few minutes, up to about an hour when comments still have to be collected; finished overlaps appear under Your Overlaps.
The dashboard shows an overlap score (the estimated share of commenters who engaged with more than one of the selected creators) and a pairwise comparison for every pair of creators, i.e. how many commenters two creators share relative to their combined commenter base. It also breaks down total, unique and overlapping commenters: total counts a person once per creator they engaged with, unique is the deduplicated number of people, and the overlap is the difference. Creators without enough public comments are excluded with a note; private or deleted accounts are excluded entirely.