There is another digital media land rush underway, as media companies, agencies and tech firms all rush to build a presence in the burgeoning world of social-media influencer marketing. The last few months have seen a spate of partnerships between publishers and influencer networks, offering advertisers cross-channel campaigns combining online influencers with their own editorial assets.

After several years of optimism fueled by fast growth and big investments from legacy media companies, the past few months has been hard on pure-play digital publishers: closings, layoffs and "strategic repositionings." But it's not all bad news. Some of the new generation of online publishers are reaching that rarest of milestones: profitability. On that note, after four years in operation, online business news publisher Quartz has joined the elite club of companies that are actually making money,