This paper summarizes research on methods for information hiding in Open Social Networks. The first contribution is the idea of StegHash, which is based on the use of hashtags in various open social networks to connect multimedia files (such as images, movies, songs) with embedded hidden data. The proof of concept was implemented and tested using a few social media services. The experiments confirmed the initial idea. Next, SocialStegDisc was designed as an application of the StegHash method by combining it with the theory of filesystems. SocialStegDisc provides the basic set of operations for files, such as creation, reading or deletion, by implementing the mechanism of a linked list. It establishes a new kind of mass-storage characterized by unlimited data space, but limited address space where the limitation is the number of the hashtags' unique permutations. The operations of the original StegHash method were optimized by trade-offs between the memory requirements and computation time. Features and limitations were identified and discussed. The proposed system broadens research on a completely new area of threats in social networks.

information hiding, open social networks, hashtag, StegHash, SocialStegDisc, filesystem