Application installation system, method and computer program product for allowing a package to be installed by a third party

A computer implemented method of developing computer applications, the method comprising providing to multiple users access, over a network, to information on a data center, with a subgroup of the users having access to a sub-portion of the information that is different from the sub-portion accessible by the remaining tenants of the subgroup; and communicating with the data center over the network employing a computer system associated with a user of the sub-group to establish application functionality with the sub-portion that may be accessed, over the network, by additional parties authorized by the user. Also disclosed is a machine-readable medium and a data center, both of which facilitate carrying-out the steps of the method.