Online Sudoku - Load / Restore
The board can be converted into text strings, so if you want to save a game, copy-paste its associated string in a safe place (or email it to yourself or to one of your friends); game restoration can be realized based on them.
Online Sudoku - The Rules
Here you can play, on the web, Sudoku puzzles online.
The 9x9 grid
The aim of a Sudoku puzzle is
Every puzzle has an unique solution.
There are no daily puzzles because you can generate a new one by clicking the desired difficulty level.