Why did my son get banned on XBL?

Off course using periods is the right way to use it! Tsssskkkk...

What are periods for? To group different words together as a sentence and to separate multiple sentences from other ones. So it's used to show groups! Groups of number quantities for example:

- 1x thousand + 1x million + 1x billion = 1000.1000.1000
- 1x thousand and 1x thousand and 1x thousand = 1000 and 1000 and 1000 = 1000,1000,1000

For here now it's proven that USA citizens can't do math...
:

Why do you have 4 digits per cluster instead of 3? It should be 100,000,000. 1's, 10's, 100's.

Comma's are used to separate items; periods are used to end a [statement]. It makes more sense that a comma would be used to separate each group of 100's rather than a period which would go at the end.