Open Geospatial Consortium Web Map Service (OGC WMS) allows a user to incorporate spatially referenced data into a geo-registered map. Utilizing WMS enables a user to access different geospatial databases without needing the original source data on local machines. This saves greatly on end user system space. Several access methods include "Get Capabilities" through a web browser or entering a link into ArcMap.
Keyhole Markup Language (KML) was developed to express geographical information into web based, two and three dimensional browsers. It was original developed for the Google Earth viewer. KML access is utilized to enable users to spatially view a tile index on a 3D globe. The index is then the access point for browsing and downloading data.
Representational State Transfer (REST) is considered fairly easy to implement and has many properties that are desired: scalability, performance, security, reliability, and extensibility.