When creating a package from ArcMap 10.0, the package can be uploaded to ArcGIS Online, my content, or saved to a file. However, ArcGIS Explorer does not support the map package (mpk) format, only layer package (lpk) format.
The idea: We should enable ArcGIS Explorer to read mpk's.
Example: User X utilizes ArcMap and creates and edits all of the maps for the company. User Y needs to view the maps but only has ArcGIS Explorer available to them. User X should be able to upload mpk's to ArcGIS Explorer so that user Y is able to view the maps. By utilizing mpk's rather than lpk's it will display the entire map that user X has created without having to group all the layers and create layer packages.