oh I'm pretty sure I've seen that a long time before. funnily enough there was a time if you had both an os x partition for Mac os and an ext2/3 partition for Linux, the only way to share files freely between the two was through a fat32 partition.
Are you referring to exFAT?
that's only since 2009 on Linux and snow leopard in 2010. in the years before, you had to do fat32.