Subscription site LinkedIn has recently acquired news aggregator and app creator Pulse for $90 million, according to the LinkedIn’s blog.The acquisition allows LinkedIn to position itself more as a publisher than social media site. (Russell Perkins, Founder of Subscription Site Central’s parent company InfoCommerce Group, speculated last Friday that LinkedIn may be becoming the iTunes Store for B2B sites, and this acquisition only backs up this claim.)For those of you unfamiliar with Pulse, the app aggregates news from a range of topics and sites and collates them into an easily-readable format. The free app currently has 30 million users in 190 countries and is used by more than 750 content publishers.In recent months, LinkedIn has taken a more aggressive stance towards positioning itself as a publisher, not a social media site, under the direction of Executive Editor Dan Roth (a former journalist for Fortune and Wired). While the company has developed extremely profitable recruiting services (most sold on a subscription basis), it’s also trying to avoid the problem of sporadic user engagement, which is common among B2B sites.With a focus on publishing, the site is easily able to increase engagement and have a more B2C angle. But with B2C subscriptions priced lower than most B2B subscriptions, it’s likely that this sort of engagement will translate into ad revenue, not subscription revenue.This may be smarter than most people think. Not only is LinkedIn augmenting one revenue stream and increasing engagement, it’s also making a clear distinction between ad-supported content and subscription-based services — a clear best practice.