Geodex.org is an implementation of Project 418. That is, it is simply one way in this the web architecture patterns used in P418 could be used to develop an end user experience.
For some examples of this, try some of the interfaces in the Interface gallery to the left and also review the Notebook repository. for some R and Jupyter examples.
The real stars of P418 are unquestionably the community of data providers. See the About section for a list of link to their sites.
For further details on the guiding principles of P418 we suggest the posting by Google: Facilitating the discovery of public data sets by Natasha Noy and Dan Brickley.
Further information and links is available in the Project 418 Publishing Notes