Twitter announced this morning that it has began opening up it's Twitter Analytics Platform to the public, a feature that was previously only open to advertising partners. This means that users can now track the "reach" of their tweets as well as track what country their post have the most reach in.
All of the data can be downloaded into a CSV file allowing users to build customized graphs, spreadsheets and presentations based on their actual Twitter analytics. At the moment all Twitter users should be able to access the data, but some accounts are experiencing issues. Twitter hopes to work out these bugs soon and says to keep checking back if you are having issues.