1. 
   GG
   abbreviation: Georgia (CIS nation on shore of Black Sea between Russia and Turkey, Armenia & Azerbaijan)
   Found op http://www.apscharts.com/abbrev.html
   
   
2. 
   GG
   (In SMS-language:) good game
   Found op http://www.mantex.co.uk/samples/texting.htm
   
   
3. 
   GG
   Abbreviation of GeekGold.
   Found op http://boardgamegeek.com/wiki/page/Glossary
   
   
4. 
   GG
   Good Game -or- Gotta Go -or- Giggling
   Found op http://www.netlingo.com/acronyms.php
   
   

Tip: double click on a word to show its meaning.