Do you have an archive of old content sitting in some ethereal back-end on your site? If so, you can harness all that “vintage” material for new online sales — especially if that content will shed light on existing trends and events.

That’s what Foreign Affairs is doing for its plus subscribers, who receive old articles and commentaries by legendary thought leaders, repackaged with a new introduction and timely updates by FA editors. For example, the publication just released an eBook collection of essays with new contributions by well-known authors and the editor of Foreign Affairs.

The bonus feature is popular with subscribers and a great way for Foreign Affairs to harness its offline strength–90 years of thoughtful analysis and prose. Instead of letting a paper-based journal yellow in the Library of Congress and the stacks of university libraries, Foreign Affairs has found a way to make it profitable for the online generation.You can find more inspiring ideas from Foreign Affairs in this week’s Case Study on our sister site, Subscription Site Insider.