When social networks became a “thing” in the aught years of this century, many big companies frantically huddled with their legal departments to mandate etiquette for their employees. Mostly, these rules were meant as a muzzle—to restrict how people represented their employer, and to some extent their professional selves, in forums and other early social venues.

A decade later, roughly half of all businesses have rules of this nature in place, according to data published last week by the Pew Research Center. A vast majority of workers (77%) dabble cyber-socially while on the job. Their top two motivations? To take a mental break from their job or to catch up with friends and family. (The survey base included 2,002 U.S. adults.)

Gulp. Those findings would seem to confirm the secret, cynical fear of managers everywhere—that allowing access to LinkedIn (LNKD), Twitter (TWTR), Facebook (FB), and other social networks might be negatively effecting productivity. “Yes it’s true,” the data whispers slyly, “eliminate that distraction lest your people stray.”

But here are the other three motivations (out of the top five) driving people to log on. All of which are quite work-related, if you think about it:

• To make and support professional connections. (Microsoft (MSFT) should be cheering this one after offering $26.2 billion to buy LinkedIn.)
• To gather information that solves a work problem
• To strengthen or build personal relationships with co-workers (That’s the sort of behavior that Facebook hopes to reinforce with its forthcoming social network for work.)

Here’s where managers come in. It turns out that employees of organizations that are more explicit and prescriptive about the ways that social networks can be useful are actually less likely to goof off on Facebook or LinkedIn while they should be working and more likely to think of it as a tool to do their job better. Guidance is good!

Social media tips from entrepreneur Gary Vaynerchuk:

Don’t worry, the vast majority of your employees aren’t gawking at their friends’ feeds while they’re supposed to be working. Unfortunately, that also means they aren’t really exploiting the potential of social networks as a business tool. Barely one-fifth of the Pew survey respondents copped to actually using Facebook for worked-related purposes (even fewer for LinkedIn).

But more than half of them said they believed that social media would help their job performance, if they felt more comfortable using it in the workplace. It may pay to think about being less restrictive, provided there are rules in place. Plus, allowing employees to take a mental break a few times daily is not a bad idea either.