What are the most commonly used open digital formats for chess games? I have many of my old games in PGN format and a still quite many in paper format that I want to make digitally available. 

I prefer make the digital versions in an open format that is widely used. 

What are the most commonly used open digital formats for chess games?
The most used is PGN. 

You can arrange them in a database once you have enoguh PGNs to make it worth it. If you have money, ChessBase is great. If you want a free option there is SCID vs. PC (SCID for Linux)

Some links:


http://en.wikipedia.org/wiki/Portable_Game_Notation
http://shop.chessbase.com/en/products/chessbase12_download
http://scidvspc.sourceforge.net/
http://scid.sourceforge.net/


Note : 

SCID vs PC is better than the Windows version of SCID. My opinion of course.