Tech's 'Dirty Secret': App Developers Scan Your Gmail

One of those companies is Return Path Inc., which collects data for marketers by scanning the inboxes of more than two million people who have signed up for one of the free apps in Return Path's partner network using a Gmail, Microsoft Corp. or Yahoo email address. Computers normally do the scanning, analyzing about 100 million emails a day. At one point about two years ago, Return Path employees read about 8,000 unredacted emails to help train the company's software, people familiar with the episode say. In another case, employees of Edison Software, another Gmail developer that makes a mobile app for reading and organizing email, personally reviewed the emails of hundreds of users to build a new feature, says Mikael Berner, the company's CEO. Letting employees read user emails has become "common practice" for companies that collect this type of data, says Thede Loder, the former chief technology officer at eDataSource Inc., a rival to Return Path. He says engineers at eDataSource occasionally reviewed emails when building and improving software algorithms.