Hey you should check keywords that became active on your account.
also check if you have your content turned on. Those could be the reason your cost went up.

Also check the import tab and see if a lovely Yahoo rep has been making changes on your behalf. In case you missed it, read here- [webmasterworld.com...]

Unfortunately the import status disappears after 30 days, so you may never know if it's been longer than that.

Is there any way to change ALL of my CAMPAIGNS to minimum bid allowed by Yahoo? I've been getting killed by them, i need to tame down my bids. I just did it for one campaign (adgroup by adgroup) and it was painful. I rarely go into my yahoo account, so I'm unfamilliar with this versus google where I use adwords editor and can change the bids on everything in 1 fell swoop. I guess not going on yahoo periodically was how I got myself in this in the first place.

Please help

1. To make sure Yahoo's editorial were not involved in the sharp cost change, you should check whether you allow ad optimization ON EVERY ADGROUP.
Yahoo tends to pause Ads with lower QS -> hence, Ads with lower CTR. Meaning that the ads that remain usually spend more than you used to spend...

2. To lower all bids to minimum: Download all your keywords to Excel, and copy the "Sponsored Search Min Bid" column over the "Sponsored Search Bid" (not the header, though) and import it in unicode - .csv format.

Good luck!

you may also want to check how much the new minimum is for kwds with high ctr. if the kwd is not helping conversion you might want to switch it off or lower bid further below minimum and watch it because Y may lower minimum bid requirement again so to accommodate your new lowered bids therefore triggering spend

One more thing, the fact that you haven't touched your account at all is more of a reason for rising costs, rather than steady costs. At least as far as it concerns working with Y!SM.

Agreed w/ Zargon! you must dedicate time to manage your bids/campaigns on a daily basis