ErgoData is a potential sidechain that could be launched on Ergo. The main idea behind Ergo Data is to serve needs of data-intensive applications, such as land registries, certificate directories etc. This would be the same (or very similar) to the existing Ergo Protocol, but with some modified parameters.
Currently, Ergo Data plans are unclear. The network will be launched only in case users will show demand for it after Ergo has established a solid infrastructure base. In case of Ergo Data chain being launched, EFYT holders at the moment of Ergo launch will get ErgoData tokens. A snapshot of EFYT holders at the moment of launch has already been done.