The ability to create custom fields, tags & groups in order build an effective learning management system with minimal effort! There are many third party addons available which make it easy/cheap but I prefer building my own from scratch as this gives me more control over how things function (and look!) - however there's nothing wrong wuth using 3rd parties if you're happy paying them :) We've been able to use our existing content repository within Moodle so we don't have any additional costs at present time although some people may be looking into other ways they might extract data out themselves once its released later next year?