The Yahoo! Search Blog just announced that they have updated their index.
We completed an index update over the weekend. As a result, you may see some changes in ranking as well as some shuffling of the pages that are included in the index. You might also be seeing a temporary spike in crawler activity. As these things go, all this should stabilize in the near future. Meantime, if you have any comments about the new index, please let us know.
Interesting to note, that Tim Mayer did not write this update entry, as he normally is the one to let us know of updates at Yahoo! Priyank Garg, Product Manager wrote this update instead.
Also, this is the first time someone mentioned an increase in "crawler activity" due to an index update. So tell your hosts to up those bandwidth limits. ;)