I used Yahoo search for a while up untill about 18 months ago. I finally gave up on them because of the time it took them to review ads/keywords. It took so long just to get a campaign live. So , recently i thought 'maybe they have improved', and as they still had £30 of my money on account i decided to give them another go but nope still the same.
I submitted a new campaign on the 9th, they immediately tried to charge my credit card with more dosh but failed because that card is now invalid

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Still i had £30 on credit and i adjusted my daily spend on this campaign (its just a test) so that the £30 would cover at lest 3 days spend. 2 days later the ads and keywords are still 'pending' review and still no answer to my email of yesterday asking how long they are going to take to review 1 ad and a handfull of keywords!
With this outfit, theres just no way you can re-act quickly to short lived merchant promotions, they will probably be over before your ads are reviewed.
Graham