Help understanding what commercial use means

[adamjthompson]

Hi,

I see that on the Yahoo & Google API agreements, they say that I may not use them for commercial purposes. Is creating my own search engine that uses the Yahoo/Google API for web results & displays ads considered commercial use? It seems it would be, but if it is, how do all of these search engines that say the search Google/Yahoo/MSN, etc, do it?

Thanks,
Adam