Here’s my 2 cents. There are already experts who have compiled lists of great, free online resources in different fields (but they’re just a list of links). You can convert those lists into content-rich learning paths on your platform and give credit to the original list creator. That might give you some momentum, at least around the learning path feature. I would also try to replicate some elements of MOOC websites, such as progression bars and notifications that show your progress on a learning path. Maybe even allow for the creation of simple quizzes. Give a simple badge for completing a learning path - it would be generic by default, but the creator of the learning path would be able to customize the badge associated with its completion. There’s so much great info on the web that doesn’t get used enough, and even the lists that pull it all together don’t get enough attention.

There’s room for this to become more than a plug-in. Your service can become a crowdsourcing platform for aggregated knowledge curation.