Susan,
I do believe many share your same struggle. I don't believe you can motivate anyone - you can only remind them of what motivates themselves. This usually comes down to having honest conversations and getting to the bottom of why certain individuals may be displaying behaviors that demonstrate a lack of motivation. This is an example of why relationships with students are the first goal for any advisor and critical. We, as career professionals, must establish rapport and trust with those we serve. This allows for open and honest discussion with students, even when we must challenge them and address sensitive topics. Rather than presuming lack of motivation is the problem, I would always coach my advisors to focus on observable behaviors (Hasn't completed a resume, hasn't submitted any applications, reports low job search activity, etc.). For instance, if having a conversation with a student, one might share observations they've made and ask the student to explain the observed behavior leading the conversation toward co-developing an action plan for the desired behavior. A phone, fax machine, email, social media and any other tool isn't what would be attributed to addressing a challenge such as a lack of motivation - they are merely tools you have at your disposal to tackle a challenge. One idea might be to share success stories with students so they can see that their classmates are getting great jobs. Using myself as an example, I would have to get release forms signed by alumni allowing me to share their testimony (story about landing their job) and a photo release form if I were to use their photo. I would then publish their stories, print them, and hang them on the outside wall of our office. I'd also ask alumni to come back and give "pep" talks to students and tips about what they should be doing now, while in school, to increase success after. These could be recorded, shared on a YouTube channel, posted on Facebook, or any other social channel you prefer. In this instance, social media would allow you to amplify your communications and impact more students if your tactic were to boost motivation by sharing success stories.
What ideas do you have to address the challenge you have observed - lack of motivation? Think of all the tools you'd use and how social media would simply be one part of a set of tools and one part of an overall strategy.
Robert Starks Jr.