"Installing" is Java's euphemism for putting files into the Java cache.
If you click on "Install" two things will happen:
- You accept Solware's (=FlyOrDie's owner) digital signature, so software (=game) digitally signed using this certificate will be enabled to run.
- Software (=game) files will be put into the Java cache so you won't have to download all files again each time you start the game.
You can control both of this on the Java Control Panel: you can delete the cache ("uninstall") and remove certificates.
The software that is digitally signed is the actual game (on the dialog above, it's Backgammon). If you accept the certificate, the game will run. If you don't it won't.
A "signed" applet will have more access to your system, than an unsigned one. However, if you download or purchase any other software, it will have the same or more rights in your system. It is up to you to decide which software you install. You either trust the author, or not. Hopefully if someone is a member since 2006, he trusts us enough to "install" the game.
Since the same certificate is used for all games, you have to do this once. All games will run afterwards.
Re: more info button: it's supposed to work. it's a java plugin bug if it doesn't.