US Patent 7779347 Systems and methods for collaboratively annotating electronic documents

Systems and methods for sharing annotations associated with an electronic document. The annotations are created by one or more annotation authors and are shared with one or more other users. A method includes determining frequently annotated portions of the electronic document and providing indicators within the electronic document of the frequently annotated portions. In one embodiment, frequently used words within the annotations are also indicated within the text of the electronic document. In addition, or in another embodiment, the annotations can be searched based on a user's location within the electronic document.