Coryne,
You have nailed the biggest issue setting up a site -- keeping it fresh and up to date. I takes lots of 'someones' time. I think you are on the right track thinking about what kind of services will draw your grads to the site (transcripts, tax forms). If they have to come to the site for these services it will force them to keep updating their information and, if your site is set up well, they'll want to keep returning. Your site will be the 'connection' you are looking for to provide them with information you want them to know, as well.
June Gudeman