There was a draft of GPLv3 that included such a clause. This was dropped with the development of Affero GPL license. The final version of GPLv3 dropped all lang

There was a draft of GPLv3 that included such a clause. This was dropped with the development of Affero GPL license. The final version of GPLv3 dropped all language regarding web services. If you want to use a GPL-like license for a web application, then the AGPL is the license to use.