> What would you do if you need to organize those
> datas in tables after that?
Hi Matthieu,

I'm a database engineer so you can guess what I'd suggest:  a database.  :)

Depending on how you plan on using the data (e.g. the number of users), you
could use SQLite or MySQL.  

ps:  I realize English isn't your first language yet you're communicating
extremely well!  "Data" is a strange English language word.  It's singular
/and/ plural which means you don't have to put an `s' at the end.  :)