Recently, when I needed to transfer the gmail emails to outlook, I've used a service that provides that transferring (from here: www.outlooktransfer.com/products/mbox-to-outlook-transfer), and it worked awesome, all my emails are transferred. But now, I'm just curious about law aspects of it. Is it completely legal for companies to take all your private emails for purpose of transferring? And how to be sure, that my emails now are not collected on 3-rd party servers?