What constitutes a “signing event”?
A signing event involves the generation of a single-use ACS Content ID digital certificate that chains up to the private root associated with the platform or carrier you are signing your applications for. For example, if you have a Windows Mobile Smartphone applications which consists of 1 cab file containing 1 exe and 1 dll file, signing your application constitutes 3 signing events: 1 each for the dll, exe, and the cab file. Note that this may be different for other platforms that VeriSign ACS supports.