Gawker Stalker is a program originally created in 2003 as a tagging system on Gawker articles. This was later expanded in 2006 to include the Gawker Stalker Map. This allowed everyday civilians to send live notifications on the locations of celebrities within New York City. Naturally, this was a severe violation of the right to privacy expected by most civilized people. While the map only operated until 2010, the Gawker Stalker tagging system continued until Gawker went bankrupt in late 2016.
SOURCES http://www.today.com/id/11945454#.Xn-7m4hKiM8 https://web.archive.org/web/20060411054843/http://www.gawker.com/news/stalker/introducing-gawker-stalker-maps-160338.php