Z:gnu-www-ja-why-affero-gpl--e16e12-But suppose the program is mai/en

But suppose the program is mainly useful on servers. When D modifies the program, he might very likely run it on his own server and never release copies. Then you would never get a copy of the source code of his version, so you would never have the chance to include his changes in your version. You may not like that outcome.