Yahoo has begun showing keyword-based advertisements on mobile phones in the US and the UK. The ads will be run from Yahoo’s mobile internet search service;

advertisers are charged each time someone clicks on one of their ads in the same way that cost-per-click works with internet advertising. Mobile advertising is at a very early stage, but Steve Boom, senior VP of broadband and mobile at Yahoo, is bullish – “I expect that the ramp will be much, much faster than it was on the PC”.