Mobile ad network Millennial Media released its first monthly Scorecard for Mobile Advertising Reach and Targeting (SMART). This extrapolates market data based on the activity it sees on its network — much like the reports we’ve covered from the likes of AdMob.

According to SMART, mobile ads now reach 31 million of the 56 million Nielsen reported mobile Web users in the U.S. (55 percent). Other top-line takeaways from the report include:

• More than 10 billion U.S. impressions in Q1 2009, with 3.39 billion in March alone
• Reach of nearly 31 million out of the 56 million Nielsen-identified mobile Web users
• The top 20 mobile handsets account for 43 percent of all mobile Web traffic on Millennial Media’s networks
• 58 percent of campaigns utilize some level of geotargeting
• Ten of the top 20 U.S. mobile designated market area by ad requests were in three states: California, Texas and Florida
• 42 percent of campaigns utilize frequency capping
• The average number of ad requests per page view: 1.09

The bit about geotargeting is interesting and relevant to local. This figure should improve with GPS ubiquity, in both frequency and targeting quality. This has implications for mobile ad revenues and CPMs (this study looks mostly at display advertising) that can demand premiums due to acute location targeting.