dstiles - 7:39 pm on Jun 2, 2013 (gmt 0)
I think they mean "within the yandex IP ranges".
I've seen extra bing and G bot IPs added from time to time over the past year or so since I initialy checked their rDNS. The yandex IPs I've been seeing don't seem to have changed much: they've added a few more bot UAs (at least, I hadn't allowed them before) but the IP changes have been few.
I have to say that despite yandex being Russia-based I have more faith in their integrity than in G right now.