Web office suites such as Google Docs offer unparalleled collaboration experiences in terms of low software requirements, ease of use, data ubiquity, and availability. When the data holder (Google, Microsoft, etc.) is not perceived as trusted though, those benefits are considered at stake with important privacy requirements. Content cloaking is a lightweight, cryptographic, client-side solution to protect content from data holders while using web office suites and other “Web 2.0”, AJAX-based, collaborative applications. Categories and Subject Descriptors H.3.4 [Information Storage and Retrieval]: Systems and Software—World Wide Web (WWW); K.4.1 [Computers and Society]: Public Policy Issues—Privacy General Terms Design, Security Keywords Privacy, Web 2.0, Google Docs, AJAX