In May, we published a Case Study on CellarTracker, an interactive database for wine enthusiasts that lets users track their wine inventory with a “voluntary payment” for memberships. At the time, CellarTracker had more than 300,000 registered users, 20,000-25,000 of which were paying subscribers, leading to an 8% conversion rate.In addition to cataloguing a wine collection, users could upload tasting notes, browse other wine reviews and estimate the value of their collection. What the site lacked was editorially independent and curated reviews — the whole model was predicated on the value of user-generated content and workflow integration. That is, users became dependent on the technology to catalog inventory and discontinuing is painful and disruptive enough to keep retention rates high.This week, CellarTracker announced a new partnership with Vinous, a subscription site run by wine enthusiast Antonio Galloni. CellarTracker plans”to integrate [Vinous’s] nearly 40,000 reviews, drinking windows, and ratings within CellarTracker for co-subscribers.”Note that term: co-subscribers. In effect, members of CellarTracker and subscribers of Vinous would get access to both sites. CellarTracker co-founder Eric LeVine told me via email, that the relationship is revenue neutral, but a mutually beneficial relationship as 1) Vinous benefits by reaching new consumers and better serving serious aficionados who spend time managing their wine cellars in detail and 2) CellarTracker aggregates a diverse set of community and professional content, further generating customer “stickiness” or retention.I wanted to highlight this deal because other database and paid content providers should be looking to strike similar arrangements. Digital media is most alluring when there’s an interactive component, but traditional media (articles, photos, videos) provide the marketing collateral needed to not only hook new subscribers, but retain current subscribers by luring them back to the site.