http://digiday.com/publishers/is-login-data-the-new-gold/#!

In case you haven’t heard, third-party cookies are dying. That means publishers’ first-party data is becoming more valuable than ever. But not all publisher data is created equal. The digital media world is elevating the already lofty status of login data, setting up a scenario where the gap between the digital haves and the have nots widens.

Log-in data is crucial because it is generally the most accurate of all data and the deepest. Services like Facebook Twitter, Google and, yes, Yahoo are kings of the hill in this regard. They have direct relationships with tens of millions of customers, affording them everything from email addresses and phone numbers, to detailed behavioral and survey-based information.

The data is rich, accurate and persistent, and that’s a promise third-party data providers have never really delivered on. What’s more, there’s a growing opportunity for those companies to use their login data to help inform ad buys elsewhere across the Web.

Login data is powerful for a number of reasons. It’s more permanent than a cookie, because users rarely change their login credentials. It’s rich, because their accounts and attached profiles tend to persist over a long period of time. And, perhaps most important, users carry their login information with them across devices. Marketers are increasingly calling for the ability to target and track users regardless of the device they happen to be using. Login data offers them the ability to do just that.