Scaling a tech company is hard enough on its own, under any conditions. Bill Weihl’s job is to make sure that the organization scales sustainably. Weihl’s title is manager of energy efficiency and sustainability at Facebook, meaning he’s responsible for making sure that the energy and resource footprint of the company’s servers is as small as possible.

The MIT graduate is also an advocate for using Facebook’s platform to help users live more sustainable lives. And that’s why he’s joining the board of Boston-based startup Practically Green, a web platform that taps into social networks and game mechanics to influence users’ sustainability behaviors.

“Practically Green is a pioneer in leveraging the power of social networks to influence employee’s actions,” said Weihl. “I am incredibly excited and impressed by what they are doing and look forward to working with the team.”

The company today launched its new enterprise platform, which lets employers engage their employees in sustainable behavior through Practically Green. The platform includes group projects, so employees can commit together to take public transportation more frequently or to conserve energy at home.

Its current clients include NBCUniversal, Sony and Unilever, among others.

The focus on enterprises makes sense both financially and in terms of impact. Businesses seeking to further corporate citizenship are substantially more likely to pay for something like this than are consumers, who are used to ad-funded web services. And corporate sustainability officers may be more likely than consumers to pore over the analytics offered on the platform, and to think strategically about which programs and activities are working and which are not.

In April of 2012, the company raised $1 million from CommonAngels, and has raised $2.9 million to date.