Executable software sent from an application service provider to a client computer can be arranged as a bundle of executable code blocks that are used during initialization of a group of applications (at least one initialization block from each application being included in the bundle). The bundle can include code for applications that are subscribed to by a user as well as for applications not subscribed to. As the subscribed applications are executed, usage data sent to a server may be monitored to determine unsubscribed applications that may be of interest to the user. Subscription offers may be automatically generated and sent to the user in response to processing of the usage data. Transmission efficiency of the code blocks may be improved by exchanging identification codes between the server and client to determine code blocks already present at the client.