Not entirely. If you're building an application based on GPL licensed code, which is not handed over to the an other party, you're not required to handover any adjustments you've made in the GPL licensed code. That's what is referred to as the 'Services as a loophole' construct (ab)used in the GPL. See also this 2007 article by Tim O'Reilly: http://radar.oreilly.com/2007/07/the-gpl-and-software-as-a-s...
Btw, The AGPL tries to prevent this loophole and does require you to share adjustments made by you on AGPL licensed code even if your only using the software as a service and the other party will not receive the application/code.
Btw, The AGPL tries to prevent this loophole and does require you to share adjustments made by you on AGPL licensed code even if your only using the software as a service and the other party will not receive the application/code.