That is cool! On the Harvard Alumni linkedin forum, there has been discussion about wanting Harvard to do the very same thing. As it now stands, a few months after graduation, you are locked out of the system. Personally, I would love that feature. Access to the academic journals and subscriptions was a great thing.
That how it was when I graduated from NCU back in 2008. And now six years later, I suddenly have library access as an alumni. That's actually a good idea on NCU's part because it could help to develop scholarship after graduation. Publish, perish or poop out.
A number of traditional B&M schools provide alumni access to ProQuest and other electronic library resources. do this. It's under consideration at Harvard; they list Brown, Columbia, Cornell and Johns Hopkins as "peer institutions" that already have this policy. At least some schools in California, like UCLA, do too.
Southern Methodist University allows alumni to access Library and Resources, but for a small fees. However, they don't ask you to pay alumni membership. I think NCU gives this free service to alumni is to expanding the community as well as part of marketing. I am wondering how the universities/colleges pay for electronic database access? Is it per license or in bulk?
I have access to proquest and a few other libraries through AMU. I'm not sure it's as extensive as NCU though.
Or it could be a way to encourage doctoral graduates to publish by providing a library. Producing a doctoral graduate is one thing, but publishing after graduation is a different issue. The fact that it cannot be used for business or commercial purposes indicates that it may be part of the licensing agreement by default.