Among the findings in the 129-page report is the fact that even people who don’t use these platforms had their data collected. The companies acquired consumer data from a variety of sources, including advertisers and data brokers, advertising tracking technology, and inferences from algorithms, data analytics, or artificial intelligence. Companies can retain this data indefinitely, the report found — and some didn’t delete users’ data in response to deletion requests. Instead, some companies deidentified data rather than deleting it, while others would only delete some data.