I run a non-profit site which has ads on it, would Yahoo! define it as a commercial site just because of the ads? http://malesopranos.com Code (markup):
If your making any kind of money with it (including Ads) it's a commercial site. If your advertising some products or services directly or indirectly but not making money, it's still commercial.
Supposedly a totally non-commercial site, with no ads or products, can be submitted free to the Yahoo Directory. However, if your make such a submission, it will likely be buried into a pile of a million other free submissions, and it might be a million years before anyone at Yahoo reviews it. In other words, your chances of ever seeing it listed in the directory are virtually zero.