A “Washington and Lee University Alumni Group” was created several years ago and managed by an alum. Last fall, we (Alumni Affairs) asked the group’s founder to offer the university administrative control in order to build and promote the group as part of an “alumni careers toolkit” and overall communications strategy. The group now has over 4,350 members having added about 1,200 over the last twelve months.
Below are 10 reasons I think the strategy to increase alumni engagment is working. I realize some of my points are subjective, but overall I think you’ll agree that if these interactions aren’t happening within your alumni Linkedin Group you probably want them to be. This is not a “Mission Accomplished” speech. We just think we’re headed in the right direction.
1) Alumni are both sending jobs for us to post and they’re doing it on their own. I believe this is crucial and probably the most important component of a successful Linkedin Group. Our W&L Alumni Group receives at least 3-5 new job opportunities per week. 
2) Administrators are taking it upon themselves to promote on-campus events that connect alumni with students. I love seeing these posts because it means our Linkedin Group is oozing into the social fabric of the university. 
3) Linkedin plays a huge part of your overall content sharing strategy. About eight months ago we launched our Alumni Perspectives program based on alumni-supplied editorials containing advice about the work world, graduate school, and work/life. Sharing these editorials on Linkedin is the perfect complement and draws alumni to the full posts on alumni.wlu.edu. 
4) You ask for content on Linkedin, and your alumni supply it. I recently asked alumni living and working overseas to send their pictures from abroad to share with the university community. I got several responses and added those pics to a Picasa Web Album, as well as tweet from @wlualum.
5) You get repeated requests to create spinoff Groups. Over the last three months particularly, I’ve received requests from regional alumni chapters, special interest (like W&L Water Polo alumni) and industry groups (W&L Lawyers). For the record, we encourage all our alumni to practice their dedication to Linkedin by creating Discussions before starting and managing a group of their own.
6) You have to scold a few alums for direct selling, asking for jobs, or starting politically hot conversations. For our group, these are three types of conversations we don’t want to harbor. However, I think they come with the territory when alums can sense a captive audience.
7) You find that group members reminisce about their time on campus. We love these!
8) The success of the alumni group yields a spinoff group that involves students. At W&L we allow seniors access to the Alumni Group but created a secondary group for all students to network with specific alumni “Career Volunteers” that have formally agreed to field inquiries. Below is the type of posts happening in that group. 
9) Alumni are promoting interesting industry or topic specific events in a particular region.
10) University administrators ask you to talk about how the Linkedin Group is functioning because there is a firm belief that it’s working to some end. I’m routinely asked to discuss the W&L Alumni Linkedin Group to various audiences including the Alumni Board, Chapter Presidents, etc.
Although I’m absolutely certain that our W&L Alumni Group is a work in progress, it’s clear that the group is fostering the type of engagement we were hoping to see when we started a year ago. One recommendation I have for those administrators working to enhance their Alumni Group on Linkedin is to recruit 5-10 alumni social media professionals to function as a guiding coalition. This group of commenters and discussion topic posters will allow you to create the illusion of engagement as you develop a culture of participation. After a few months, you'll likely see huge increase in organic posts as opposed to those you've solicited from your guiding coalition.