How does the datastore system work?

[Andreas]

Well the advantage is that you don't need an additional query, as init.php will load all required rows with just 1 query.
So it is easy to store custom data without having to modify existing queries or introduce new ones.
I'd suse this for data that needs to be read often/all the time, but is only being updated seldom (as you can see, datastore holds things like user record, smilies, bbcode, etc).