I know its a pain but you can request an xls file from yahoo and specify your required exclusions on there.
Go into a "campaign" then go into a specific "ad group" click "ad group settings" (not the drop down) click the "edit" button on the "tactical settings" box Find the "exclude words" on the left side of the screen under "match type" and click "show" Now you can enter the words you want to exclude.
Transburgh is correct. I was wondering the same thing but it was exactly in the tactic settings within the Ad Group area. Note though Yahoo also states, "Excluded words only apply if the advanced match type is enabled for Sponsored Search." So maybe if you are in standard mode, the exclude section doesn't appear. Before, I had even searched Yahoo's help section (which is terrible) and it didn't provide any information about excluding keywords. I typed in "exclude keywords' into their search window while on the Ad Group and received results about "choosing keywords" and some other non-relevant links. Thanks Transburgh! Most people probably don't even use negative (or excluding) keywords. Big mistake especially now that Yahoo moved to the new quality index bid pricing.
Problem here is you cannot exclude exact matches. So if there are phrases that are made of good words but you have high organic results for your ads show up and you are wasting money. The answer is to only do excact matching for your ads. This is not good for you or Yahoo. Google lets you exclude exact phrases. For this reason I really dislike yahoo. I think they know this about their system and are taking their advertisers for a bunch of dummies - not this one though.
I have followed the above instructions exactly, and looked in both the campaign as well as the ad group settings, but this no longer seems to be how negative words are added? Any suggestions? (and why does it have to be made so difficult - yes this question is rhetorical)
Agreed. I had missed it. For anyone else looking for this, the instructions are correct, after landing on the "Ad Group Tactic Settings" page, look at the right hand side of the screen and will say: