Google+Docs

Google states that it has the rights to the content submitted by the user under its terms of services. "9.1 You acknowledge and agree that Google (or Google’s licensors) own all legal right, title and interest in and to the Services, including any intellectual property rights which subsist in the Services (whether those rights happen to be registered or not, and wherever in the world those rights may exist). You further acknowledge that the Services may contain information which is designated confidential by Google and that you shall not disclose such information without Google’s prior written consent.” and also that it has “8.3 Google reserves the right (but shall have no obligation) to pre-screen, review, flag, filter, modify, refuse or remove any or all Content from any Service "

The purpose of this is to ensure the protection of Google's IPR and to protect Google being responsible for illegal activity