Take a look at SetPref() and GetPref(). These commands can be
used to save and retrieve data locally.
If you want to share data among users (for example, for a
high-score table) then one standard technique is to use PHP scripts
and a MySQL database on your server. You can use getNetText() or
(better) postNetText() to talk to your PHP scripts and retrieve the
data that they generate.
A third approach would be to use a third-party xtra, such as
to read and write data to an FTP site.
If you need more details about any of these approaches, then
please provide a bit more background information about what you are
trying to do and what data you are hoping to save.