1. A method that facilitates file access control of a network storage service, the method comprising: providing, on a network storage service, a third-party application database comprising a plurality of descriptions of third-party software applications configured to access files on the network storage service, wherein each respective third-party software application description: is registered by a respective third-party application developer, and includes application title, client ID, supported MIME types, and a unique application-specific ID, wherein the client ID included in each third-party software application description is: only known to the respective third-party application developer and a query processing component of the network storage service, and accessible by the third-party software application and the third-party application database; providing, on the network storage service, a user data store comprising files associated with users, each file within the user data store having an associated MIME type comprising an application-specific ID corresponding to an application which created the file, and a file identifier; receiving a file access request at the network storage service over a communication network from a third-party software application operating on a computing device, the file access request including a client ID for the third-party software application and a file identifier for a specific file; performing a query, by the query processing component, based on the file access request, in the third-party application database to select a particular third-party software application description from the plurality of descriptions based on the received client ID included in the file access request; determining a first application-specific ID for the selected third-party software application description; locating a file from the user data store having a file identifier that matches the received file identifier included in the file access request; extracting a second application-specific ID from a MIME type associated with the located file; and granting access to the requested specific file in the user data store to the third-party software application in response to a determination that the first application-specific ID associated with the selected third-party software application description matches the second application-specific ID from the MIME type associated with the located file.