I'm a recent user of Presto and Hive at Facebook after being here coming up to three years. I've been using them primarily to understand ways in which we might be sending people's traffic to non-optimal locations, or non-optimal paths between our CDN and the source content, or to help with understanding current and extrapolating future capacity needs on our CDN (total requests, changes in cache hit object/byte rates, &c.)

I imagine that they could use it to track how many cats walk across peoples keyboards daily, and what peak "cat walking on keyboard" hours are. I'd be more than mildly interested in the results.