1. A computer-implemented method for adding information to a spreadsheet, comprising: on a client system having one or more processors and memory storing one or more programs to be executed by the one or more processors: displaying a spreadsheet; receiving a request to add a cell value to the spreadsheet, the request containing a reference to an object and an attribute; generating a query corresponding to the request; sending the query to a fact repository; receiving the requested cell value from the fact repository, wherein the cell value correspond to a value of a fact, the fact being associated with an object in the fact repository, wherein a respective fact includes an attribute field indicating an attribute and a value field describing the indicated attributes, wherein objects in the fact repository are created by: extracting facts from web documents; determining entities with which the extracted facts are associated; storing the extracted facts in the fact repository; and associating the stored extracted facts with objects corresponding to the determined entities; inserting the received cell value into the spreadsheet.