1.Shorthand for Got to Go or Good to Go, G2G also abbreviated as GTG and is a term often used in chat communications and computer gaming. Below is an example of how this could be used in chat.
User1: Ok I've G2G
User2: Ok CU
<User1 has disconnected>
2.Short for government to government, G2G is the sharing of electronic information between government agencies or departments. The idea of and push for G2G is to help improve communication between government agencies and departments and to promote the sharing of information between them.