That has happened before with Korean spam but since the board is clean now, it seems the italki team knows how to handle it now :)

Probably not much. It's more of an annoyance to the users. The posts are just plain text which are pretty small in terms of modern computer usage. There are a lot of them by our standards but not by the standards of a site this size. I didn't notice any slowdown when they were coming thick and fast yesterday.

Thanks!