SUNNYVALE, California: Internet portal Yahoo has started to air keyword-based ads on cellphones in the US and the UK in its first effort to establish a mobile-advertising business outside of Japan.

The trial will allow users to perform keyword web searches on most cellphones and hand-held devices, starting with a select group of less than 100 unidentified advertisers.

Yahoo will charge clients each time a consumer clicks on the link shown in their ad. Rates appear to be comparable to those for PCs but in time could prove to be even more lucrative.

Data sourced from Wall Street Journal Online; additional content by WARC staff