Yahoo Small Business - smallbusiness.yahoo.com

16/12/2009 More expensive per click than Google Adwords in my opinion and a lot less traffic ... but at least they don't kick you off for no reason every so often or ban your ads citing "poor landing page" quality when you know there is no way they had time to evaluate your landing page between placing the ad and it being labelled poor! They're just forcing you to pay £5+ per click.

Yahoo Small Business Homepage