This question evaluates a data scientist's skills in product analytics, experiment design, metric definition, and causal inference for a group-based social feature launch.

You are evaluating whether to launch a sticker-reply feature in Facebook Groups. The feature allows members to reply to posts or comments with a sticker (a lightweight, expressive response) in group threads.
Assume: the feature is available only inside Groups; users may belong to multiple groups, and group interactions can influence others (network effects).
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