On the Yahoo Search Marketing end, go to the Campaign Tab > Import > Import 3rd Party Campaigns.
Here are the necessary steps:
- Download the third-party campaign to a file on the appropriate site.
- Open the file on your computer. Make sure it's in CSV or ZIP format and adheres to the guidelines for YSM.
- Convert your third party campaign file with an appropriate name that is easy to remember.
- Download and review the converted campaign file by choosing the Download link.
- Import the converted campaign file.
So far, one person has tried it and it worked well with the exception of one small issue: Yahoo sees some keywords as duplicates whereas other campaigns on other sites do not have these restrictions.
Forum discussion continues at Search Engine Watch Forums.