SGS is a graph data web syndication format. Its name is an acronym for simplegraph syndication. SGS is a dialect of XML. All SGS files must conform to the XML 1.0 specification, as published on the World Wide Web Consortium (W3C) website. The goal of SGS is to provide sites with a standard way to publish graphing data.

Here is the schema that shows the documented structure of a SGS feed.
http://developer.trendrr.com/sgs/sgs-schema.xml

Here are some sample SGS feeds.
http://trendrr.com/api/feeds/graph?id=381053&return=xml
http://trendrr.com/api/feeds/graph?id=378706&return=xml

SGS 0.1 is offered by Trendrr and Wiredset under the terms of the Attribution/Share Alike Creative Commons license.