The New York Post is blocking iPad Safari users from accessing content without the use of the New York Post app. Interestingly, other browser apps on the iPad do not appear affected as described below. When using Safari on the iPad and attempting to log into the New York Post, the user is taken to a different page. That page explains the New York Post is available only through the New York Post app.
The New York Post app costs $1.99 and allows in app subscription purchases. The New York Post app description states:
The New York Post iPad App provides a new way to experience The Post’s award-winning coverage. In each day’s edition, you will find all the key sections of the newspaper – News, Page Six, Opinion, Pulse, Business and Sports. You’ll also experience a bevy of special features such as the ability to make your own front page and share it with The Post or your friends; viewing photo galleries and videos while you read the paper; sharing stories via e-mail, Facebook and Twitter; saving any newspaper issue you want to keep; and for sports fans, you can set the app so you start reading from the Sports section every day. And make sure you tap the American flag on the front page! The New York Post is committed to providing you with hard-hitting news coverage, bold headlines, world-class gossip and the best sports in town in a new digital experience. Read The Post anywhere, anytime — each morning on your way to work, over a sandwich at lunch or during the evening commute home. You can read the edition in portrait or landscape mode while enjoying additional photos and videos not found in the paper. The $1.99 download fee entitles you to an introductory 30-days.
By using the app created by the publisher, you may get more or different content.
Currently, other iPad browsers can access the NY Post. Those browsers include Dual Browser, Duet Browser, DNoteIt, Maven, and S-Pad. They are not currently affected by the redirect message created by using the Safari browser.
So, it appears that the New York Post is specifically detecting the Safari browser, and not other browsers for purposes of redirecting the user to the message.