Yahoo's Marissa Mayer has said that the search partnership between the tech firm and Microsoft has not been as lucrative as expected.

The CEO, brought on board in 2012, does not believe that the collaboration has resulted in neither the market share or revenue that the firm predicted.

Speaking at the Goldman Sachs Technology and Internet Conference in San Francisco on Tuesday, Reuters reports that Mayer said the companies want to "collectively want to grow share rather than just trading share with each other," and at the moment, Microsoft's Bing search engine isn't quite making the cut.

"I'm not confused. Our biggest business problem right now is impressions. Basically can we grow impressions, can we get growth happening here. We need to see monetisation working better because we know that it can and we've seen other competitors in the space illustrate how well it can work. We've seen some gains but we need to see more." Mayer commented.

In 2010 Microsoft and Yahoo! signed a ten-year collaboration to provide a web search system which would hopefully prove a competitor to Google's search engine, and provide more advertising revenue to boost Yahoo's cash flow. However, the scheme has not performed as expected, and so the 37-year old CEO has to begin looking at other avenues.

Mobility is also on the new CEO's mind. Yahoo has bought a number of companies that create mobile apps over the last year, and plans to ditch any mobile apps that are no longer suitable for Yahoo's "focus areas," potentially shrinking the app range from about 70 to a dozen. Mayer believes that Yahoo should be a place people turn to to make daily Internet activities more interactive and easy, and by slashing the number of apps available this can be achieved -- as well as providing a better focus for advertisers to invest in the tech firm.