Part of it seems to be a play to get more governments, who often have A LOT of geo data on Github. Github is in many ways positioning itself to be a public repository of data, not just code.
Speaking of that, among all the startups that target developers, I've noticed a dearth of startups that focus on providing database backups with versioning, including functionality for functionally defining how to roll back to previous versions of a database and merging or "rebasing" of databases.