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You can obtain multiple listings if you site content warrents it and is organized to take advantage of them. Commercial sites must pay for each listing submission. Non-Commercial Sites are free.
The best way to create a strategy for multiple listings is through study of existing multiple listings in the directory.
I had the problem once where I submitted (and paid for) each main sub-directory of my large site as they sort of told me that was ok (Having already been listed and wanting to compete more like other sites, I submitted a main sub-directory on my same site, it got denied because of some dumb reason, then got approved when I appealed), so I went ahead and submitted more, which all got denied because they all belonged to the same site!!
In the end, Yahoo and I agreed a deal where they listed all the important keywords in my description! Which is key; get those keywords in your URL, Title and / or description. And then you do not have to worry :-)
The best results from yahoo come from following their rules (until you know how to break them) and learn from what is working by studying the high ranking sites within. Don't try to re-invent the wheel, just focus on improving it (your site) by offering more than anyone else. You have an advantage. Your listed competitors have already played their hand (for the moment), so use what they have done to help you "leapfrog" over them.