We are in a constant state of information overload. Some organizing principle needs to be applied in the information noise in order to form a usable knowledge base. Stackability is ana appropirate solution. Microcontents are complete, closed information units in themselves, which can be understood in a short time, and are accompanied by a set of meta-data that can be used to easily connect to other microcontents. The stackability of microcontents goes beyond this weak connection, since an author can produce new communicable content by selecting available content and linking it paralelly to or consecutively. The metadata of the elementary micro-contents can be read from the complex content units, so that creative communities are able to quickly accumulate a structured knowledge treasure, where metadata describing the circumstances of the creation of each base-content unit is available.

Certificates are veriying the quality of the content. This requires issuing certificates for the existing content element, such as an event or learner-performance. At BME we run our certificate management system called DCP Host. DCP implements the Open Badge 2.0 standard certified by the 1EdTech consortium. This host allow us to issue digital certificates, in a form of special badge-image file with "baked in" metadata. Some BME faculty awards and achievements are issued digitally, relying on the DCP system.

The possibility of aggreagetion and stacking modules has arisen in the learning recognition needs. The OB2.0 open standard does not specify stackability in detail, but it allows it, so we developed it within the framework of an EU project. Based on surveys and theoretical considerations, we defined logical rules for creating meta-badges. The stacking function of DCP monitors the quantity and quality of base-certificates distributed to the awardee, and issue stacked digital certificates if pre-set rules are met. The paper provides insight into this development.