afaik it's pretty common within gaming communities
e.g
1k - 1 000 (of gold)
1kk - 1 000 000 (of gold)
1kkk - 1 000 000 000 (of gold)
>I can't say I would recommend the practice.
Oh, I just realized that somebody may think about other kkk...
damn, but with number in front of it it's just like yet another unit - I guess?