lucy24 - 8:34 am on Jan 31, 2013 (gmt 0)
At least so far the IPs do seem to belong to Yandex. It isn't as hopeless as, say, the MJ12bot which can come from absolutely anywhere-- including a good many blocked server farms. And, conversely, you don't see a lot of Yandexbot spoofers. Fake yandsearch* in referers, yes. Fake UAs, not so much.
* I did some quickie experimenting. The fake referer isn't any different from a real one. Except that currently mine all end in &lr=213. I don't know what "lr" is, only that it doesn't correspond to "cd".