A Yahoo! executive took to the blogosphere yesterday to spell out why Yahoo! is a huge mobile player – and it has been for a while.

Specifically, Paul Cushman, head of mobile ad sales at Yahoo!, said he understands why many pundits want to weigh in with their own ideas and storylines about the company given the headlines recently. Last week, Yahoo fired CEO Carol Bartz, sparking all kinds of speculation about the company’s board, its future and amplifications about past missteps.

But prevailing opinions about mobile haven’t been capturing the full picture, Cushman said, who went on to list quite a few significant steps that Yahoo has taken over the years.

Yahoo reaches 56 million unique mobile web users a month in the United States, for a 51 percent reach of the overall U.S. mobile market, making it the No. 3 mobile brand, he said.

Yahoo also was the first major search company to launch a search product designed specifically with mobile in mind, with oneSearch in 2007. Yahoo! Go was way ahead of the market when it first launched in January 2006, he said. It enabled email, uploading photos, mapping and search via Yahoo’s oneSearch and Yahoo! Answers service, stock quotes and breaking news.

Yahoo has more than 100 partnerships in mobile around the world and AT&T recently made Yahoo its home page on all Android and RIM devices.

Cushman’s blog is the first of a new series where Yahoo! employees share their stories about the company.