We present methods for monitoring a large, diverse, and autonomously modified collection of healthcare documents on the Web. Our methods do not require documentproviders to offer any special services. They are based on explicating changes between document versions on a per-user basis by using differencing algorithms. These changes are presented to users in the context of the documents using special XML elements. In order to effectively browse changes in large document collections, we use a variable-resolution XML browser. A noteworthy feature of this browser is that it produces usable displays at any level of detail specified by a user.