Since "unroll.me" was anonymizing data[1] and then sold that data to Uber, is it safe to assume that Lyft used the subscription service to manage their drivers/customers contact information? If not, it's not clear to me how "unroll.me" provided that data to Uber.
[1] quote from article: Using an email digest service it owns named Unroll.me, Slice collected its customers’ emailed Lyft receipts from their inboxes and sold the anonymized data to Uber
https://unroll.me/ is a service that searches your inbox to see what potentially-unwanted emails you're subscribed to, and automates the process of unsubscribing from those emails.
So they had access to the inboxes of people who happened to be Lyft customers, without any business relationship with Lyft.
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Apparently, if you're not paying for it, you're, yet again, the product.
[1] quote from article: Using an email digest service it owns named Unroll.me, Slice collected its customers’ emailed Lyft receipts from their inboxes and sold the anonymized data to Uber