Facebook has taken some steps to prevent companies from recklessly using your data for targeted ads, but now it might put pressure on them to come clean. As of February 28th, Facebook's "why am I seeing this ad?" button will show who (if anyone) uploaded the contact info that led to a sales pitch. You'll know if it comes straight from the source, like a retailer, or if the company relied on an outside partner to gather the data.
Previously, Facebook would show only which company was using the contact info.
This won't completely stop data misuse. It should, however, explain how advertisers obtained your data and give you more chances to limit access to your data in the future. TechCrunch also noted that it could help Facebook catch ad partners who are uploading info without consent -- and that, in turn, might have unscrupulous companies thinking twice about harvesting customer info without asking. While Facebook might not be as transparent as some would like with its ad policies, this could be a step in the right direction.