9. A system for providing annotation information associated with web content, the system comprising: a data processor configured to communicate with multiple computerized devices associated with respective authors of webpage annotations; and an annotation information repository configured to store a plurality of collections of annotations, each of the plurality of the annotations collections having been authored by an associated annotations author and corresponding to an associated webpage, such that each of the plurality of the annotations collections includes one or more annotations relating to corresponding one or more portions of webpage content of the associated webpage, wherein the data processor is configured to perform operations comprising receiving, from a computerized device from among the multiple computerized devices that is associated with a specified author, a request to retrieve an annotations collection from among the stored plurality of annotations collections, the annotations collection referenced in the received request having been authored by the specified author, and corresponding to a specified webpage being accessed by the computerized device associated with the specified author from a webpage server system, the annotations collection referenced in the received request including one or more annotations relating to corresponding one or more portions of webpage content of the specified webpage, retrieving, from the annotation information repository, the annotations collection referenced in the received request, and transmitting the retrieved annotations collection to the computerized device to enable the computerized device to concurrently display the transmitted annotations collection and a current instance of the specified webpage, in such a way that the one or more annotations included in the transmitted annotations collection would be overlaid on the corresponding one or more portions of the webpage content of the specified webpage.
13. The system of claim 9 wherein the data processor is further configured to perform operations further comprising updating a stored instance of an annotations collection upon receipt from the computerized device of an updated instance of the annotations collection that includes a created or removed annotation corresponding to a portion of webpage content of the current instance of the specified webpage.