1. A computing system for scalably managing annotations, the computing system comprising: a tier III server storing data for the annotations; a tier II server separate and distinct from the tier III server, said tier II server maintaining a tier II index of the data for the annotations stored on the tier III server; and a tier I server separate and distinct from the tier II and tier III servers, said tier I server maintaining content information indicating if a content source has data indexed by the tier II server; wherein data for the annotations is not stored on any of the tier I server and the tier II server; wherein the content source is not stored on any of the tier I server, the tier II server and the tier III server; wherein the tier I server, based on the content information maintained by the tier I server, responds to one or more client requests for annotations associated with the content source with index information that permits the client to retrieve a tier II index associated with the content source; wherein said tier II index includes a plurality of generic properties for the annotations and wherein the tier III server further stores one or more type specific properties for the annotations; and wherein the tier III server further stores client software to allow a user to view a type of annotation and the annotation properties including the generic properties and the type specific properties, said tier III server transmitting the client software to the client when a viewer needed for the annotation type is not present on the client.