The British use it as a decimal point and use the comma for every three numbers as well, Ie:
1,000
10,000
100,000
1,000,000
like that.
in the netherlands it's like this:
the market rates have dropped by 7,5%("," insteed of a ".")
and you won $1.000.000("." insteed of a ",")
it's really the other way around