Im just starting/learning to build a php based RPG game.

i have a model game that im looking at.

and they dont use Mysql at all.

all the account info. and etc etc are stored in .dat files.

im wondering. should i follow what they did there and just store stuff on the .dat file

or should i use Mysql to store info.

what would be a a better way to deal with 100+ user game (just an example)?