It says it reaches 82 percent of US mobile web usage, producing its information by analysing the devices, operating systems and carriers through their connections to the apps into which it serves its network's adverts.
It's also important to understand these figures are generated by mobile devices active on the internet; something likely to highlight newer smartphone devices such as iPhone and those running Android.
Hence what's most significant about these figures are the trends they provide.
Trend reversed
June 2010 proved to be a rather strange month, reversing many of the changes seen in May.
For example, during May, Apple's estimated share of the smartphone OS mix dropped 14 percent to 48 percent, while in June it's back up to 56 percent of the total.
Similarly, RIM dropped two percent to 17 percent, compared to 19 percent in May.
Android dropped four percent to 11 percent. In May it was up five percent.
To that extent, the smartphone OS mix in June was much as we found it in April: Apple at 56 percent, RIM 17 percent, Android 11 percent, Windows Mobile at 4 percent and Palm at 2 percent.
In comparison though, the most recent comScore report for the US smartphone market, which is based on a survey rather than internet usage, had RIM at 41.7 percent, Apple at 24.4, Windows Mobile 13.2, Android at 13 and Palm 4.8.
Smaller slice, bigger cake
Yet, underlying Millennial's figures is the growth of the overall mobile ad market.
On an absolute level, it's better news for RIM and Android. Ad requests to BlackBerry devices increased 6 percent month-on-month. The format is up 41 percent since January 2010.
Similarly, Android ad requests were up 23 percent month-on-month and 439 percent since January.
Apple saw the biggest monthly jump however, up 36 percent, while the explosively increasing iPad sector is up 206 percent.
Drilling down
In terms of actual device activity, iPhone remains the number one, of course, followed by BlackBerry Curve. The Motorola Droid and Nexus One are ranked fifth and six behind two Samsung smartphones.
While Millennial reckons Apple is the top phone manufacturer in the US with 29.5 percent market share, Samsung is second on 17 percent, RIM third with 9.1 percent, Motorola fourth with 7.7 percent and HTC fifth with 6.4 percent.
Six of the top 20 smartphone run Android and four run BlackBerry OS.
You can read the full Mobile Mix report for June on Millennial Media's website.
