A computerized method, comprising: at a portable storage device: retrieving a list of a plurality of applications stored at the portable storage device, wherein each application of the plurality of applications has a corresponding private filesystem, where each application together with each corresponding private filesystem is enclosed in a security sandbox that prevents another application of the plurality of applications from accessing that private filesystem, and wherein a host device can access said private filesystem via a shared filesystem; for each application of the plurality of applications: determining if the application will share at least a portion of the corresponding private filesystem to the shared filesystem of the portable storage device, wherein the shared filesystem is configured to share files with the host device that is coupled to the portable storage device, and adding, to the shared filesystem of the portable storage device, a link to the corresponding private filesystem if the corresponding private filesystem is shareable based on the determining step, wherein the link allows access to the corresponding private filesystem; and advertising the shared filesystem of the portable storage device to the host device. at a portable storage device: retrieving a list of a plurality of applications stored at the portable storage device, wherein each application of the plurality of applications has a corresponding private filesystem, where each application together with each corresponding private filesystem is enclosed in a security sandbox that prevents another application of the plurality of applications from accessing that private filesystem, and wherein a host device can access said private filesystem via a shared filesystem; for each application of the plurality of applications: determining if the application will share at least a portion of the corresponding private filesystem to the shared filesystem of the portable storage device, wherein the shared filesystem is configured to share files with the host device that is coupled to the portable storage device, and adding, to the shared filesystem of the portable storage device, a link to the corresponding private filesystem if the corresponding private filesystem is shareable based on the determining step, wherein the link allows access to the corresponding private filesystem; and advertising the shared filesystem of the portable storage device to the host device. retrieving a list of a plurality of applications stored at the portable storage device, wherein each application of the plurality of applications has a corresponding private filesystem, where each application together with each corresponding private filesystem is enclosed in a security sandbox that prevents another application of the plurality of applications from accessing that private filesystem, and wherein a host device can access said private filesystem via a shared filesystem; for each application of the plurality of applications: determining if the application will share at least a portion of the corresponding private filesystem to the shared filesystem of the portable storage device, wherein the shared filesystem is configured to share files with the host device that is coupled to the portable storage device, and adding, to the shared filesystem of the portable storage device, a link to the corresponding private filesystem if the corresponding private filesystem is shareable based on the determining step, wherein the link allows access to the corresponding private filesystem; and advertising the shared filesystem of the portable storage device to the host device. determining if the application will share at least a portion of the corresponding private filesystem to the shared filesystem of the portable storage device, wherein the shared filesystem is configured to share files with the host device that is coupled to the portable storage device, and adding, to the shared filesystem of the portable storage device, a link to the corresponding private filesystem if the corresponding private filesystem is shareable based on the determining step, wherein the link allows access to the corresponding private filesystem; and advertising the shared filesystem of the portable storage device to the host device.