While growth in the overall spend in search advertising in the United States showed signs of slowing down in the second quarter of 2012, mobile search advertising continued its strong growth, according to a new report from IgnitionOne.

Spending on mobile search ads during the second quarter skyrocketed 333 percent while overall search advertising spend grew just 15.5 percent, which is nearly half the growth of last year. The results point to the growing use of mobile devices by consumers to search for information, with marketers reallocating search spend to invest where their audience is.

?Even with the past enormous growth in mobile search advertising, there is still continued opportunity,? said Will Margiloff, CEO of IgnitionOne, New York.  ?And even as the overall growth in search spending slows, mobile continues to accelerate in growth with 333 percent year-over-year.

?The past two quarters showed impressive growth that we had predicted would continue, but mobile search advertising spending growth even outpaced those amazing past quarters,? he said. ?At some point the growth will level off, but it does not look like that will be soon.

?As network speeds, processing power and adoption of mobile devices grow, we will continue to see growth. The fourth quarter will be the most interesting as we see how much mobile will come into play with holiday campaigns.?

Engagement grows
As a result of the growth in the spend on mobile search advertising, mobile now accounts 14 percent of total search budgets, up from 12 percent a year ago. Mobile search ads also displayed greater growth in engagement as clicks grew 325 percent while impressions grew 130 percent.

The growth in these numbers is accelerating compared with previous quarters, according to IgnitionOne.

The numbers also point to the strength of tablets in search, with tablet devices accounting for 60 percent of the total mobile search advertising budget for the quarter.

The growth in mobile search is also being felt at Google, where CPCs continued to decline and were down 3.1 percent during the second quarter, driven in part by the increasing reliance on mobile, which has cheaper CPCs than desktop search. The decrease is slowing and was not as large as in previous quarters, per the report.

Overall, cost-per-clicks grew by 2.1 percent during the second quarter.

Travel embraces mobile search
Other findings include that Yahoo!/Bing continues to outpace Google spend growth in the U.S., with Yahoo!/Bing growing 32.9 percent during the quarter while Google grew only 11.4 percent. However, Yahoo!/Bing?s growth is off of a smaller base.

The report also found the travel sector posted a higher growth rate in search ad spending compared with overall search driven ? 37.8 percent vs. 15.5 percent - in part, because of the focus on mobile and tablet search in this category.

?It continues to be clear that mobile is becoming an important channel for search marketers,? Mr. Margiloff said. ?Consumers are using mobile more and more and it is important that you not only reach them where they are, but optimize their experience once they click through.?

Final Take
Chantal Tode is associate editor on Mobile Marketer, New York