Publishers may see traffic spikes from stories they share on Facebook and Twitter, but that’s nothing compared to the loyalty engendered among those who have bookmarked their site and come back to it frequently according to a new Pew study.

That’s particularly apparent when you look at time on site, pages per visit and overall number of visits per visitor; in other words all the metrics that matter for online publishers. People who have bookmarked a site over-index in all those categories.

The study said those engagement metrics were important for not just those who bookmark a site but all those visit via “direct” methods, meaning any visit that doesn’t have a referring site.

So what does that mean for publishers? It means that those vaunted Facebook and Twitter visitors are important for drawing eyeballs to a single story, sure, but they aren’t good at creating any sense of reader loyalty. Those visitors have little to no interest in digging any deeper into the site’s archives or related stories. So as important as it might be to convert those Facebook fans into readers, it’s even more important – for page views, ad revenue and other important business metrics – to convert those single-visit readers into long-term readers, people who have an affinity and loyalty to the site and its content.