È necessario includere il testo della licenza GPL / LGPL su ogni copia distribuita del mio programma? O posso semplicemente mettere un link in About -dialog?
Sì, perché il link potrebbe non essere valido tra 5 o 10 anni.
Sì, è necessario. Non puoi semplicemente includere un link che punta al testo della licenza. Il motivo è chiaramente indicato nelle domande frequenti su GNU :
Why does the GPL require including a copy of the GPL with every copy of the program?
Including a copy of the license with the work is vital so that everyone who gets a copy of the program can know what his rights are.
It might be tempting to include a URL that refers to the license, instead of the license itself. But you cannot be sure that the URL will still be valid, five years or ten years from now. Twenty years from now, URLs as we know them today may no longer exist.
The only way to make sure that people who have copies of the program will continue to be able to see the license, despite all the changes that will happen in the network, is to include a copy of the license in the program.