This document discusses the topics of geolocation, geotagging, and how location data is used across various technologies and platforms. It provides definitions for terms like geolocation, GPS, GIS, geo-IP, and geotagging. It also summarizes how location data is used on social media platforms like Facebook, Flickr, and Twitter. Examples are given of location-based apps like Foursquare and Gowalla. The document suggests ways libraries can utilize location data, such as for targeted advertising, market research, and geo-authentication. Overall, the summary discusses emerging technologies related to geolocation and how location information is captured and applied in various contexts.