1. A computer-implemented method of providing information about content of an electronic book (ebook) displayed at a client device, the method comprising: determining a set of layers available for use with the ebook displayed at the client device, one or more layers of the set of layers providing one or more types of information associated with one or more types of ebook content at one or more positions in the ebook; transmitting, to the client device, a list identifying the available layers in the set; receiving, from the client device, an identification of a layer, from one or more matching layers, that was launched by the client device and a position range of activated ebook content, the one or more matching layers determined, from the list of available layers, as being able to interact with the activated ebook content according to a type of the activated ebook content; translating the received position range to a translated position range associated with an indexed version of the ebook different from a client version of the ebook displayed at the client device; identifying the layer information associated with the ebook content identified by the translated position range, the layer information identified specific to the launched layer; and transmitting, to the client device, the identified layer information for display in conjunction with the activated ebook content identified by the received position range.
1. A computer-implemented method of providing information about content of an electronic book (ebook) displayed at a client device, the method comprising: determining a set of layers available for use with the ebook displayed at the client device, one or more layers of the set of layers providing one or more types of information associated with one or more types of ebook content at one or more positions in the ebook; transmitting, to the client device, a list identifying the available layers in the set; receiving, from the client device, an identification of a layer, from one or more matching layers, that was launched by the client device and a position range of activated ebook content, the one or more matching layers determined, from the list of available layers, as being able to interact with the activated ebook content according to a type of the activated ebook content; translating the received position range to a translated position range associated with an indexed version of the ebook different from a client version of the ebook displayed at the client device; identifying the layer information associated with the ebook content identified by the translated position range, the layer information identified specific to the launched layer; and transmitting, to the client device, the identified layer information for display in conjunction with the activated ebook content identified by the received position range. 4. The computer-implemented method of claim 1 , wherein the layer that was launched by the client device includes a named entity layer, wherein identifying the layer information comprises: identifying one or more named entities referenced by the activated ebook content identified by the translated position range; and obtaining entity data for the one or more named entities referenced by the activated ebook content identified by the received position range, and wherein the identified layer information includes the obtained entity data for the one or more named entities.