Mobile advertising network AdMob has released its metrics report for March 2010, taking a closer look at Google’s Android OS and its increasing share of the mobile market. The report also reveals that the Motorola Droid is the leading Android handset.

The number of Android devices available as of March 2010 is vastly greater than the number available just seven months ago. AdMob notes in its report that in September 2009, two devices — the HTC Dream (or G1) and the HTC Magic (the myTouch 3G) — accounted for 96% of all Android traffic. As of March 2010, 11 different devices accounted for 96% of Android traffic.

Check out this chart, which shows which Android devices are generating the largest amount of traffic:

The Motorola Droid is the big winner, responsible for 32% of Android traffic in March 2010. Conversely, the Google Nexus One only generated 2% of Android traffic. Looking at the full data from AdMob’s report, it’s clear that although the operating system has really only made waves in the U.S., the Droid is the undisputed Android champion overall. To us, this speaks volumes about the power of Verizon’s network.

iPhone Still Leading the Pack

However, it’s important to note that even though the iPhone is still the smartphone and mobile device leader (even if you add up all other handsets collectively based on OS, iPhone is still in the lead), breakout successes on other platforms could easily change things.

Android OS Fragmentation?

This presents some hurdles for application developers who need to either make OS-specific versions or ensure backward compatibility across all major OS versions.

AdMob’s report shows that Android use is split across the three major releases of the platform: Android 1.5, Android 1.6 and Android 2.0/2.1. Android 1.5 has 38% marketshare — which makes sense, considering it is what most of the older Android devices still run — Android 2.0/2.1 has 35% of the market and Android 1.6 has 26%.

The problem for end-users is that the version of the OS you receive is largely dependent on the manufacturer of your phone and its relationship with your wireless carrier. Verizon Droid owners got Android 2.1 in the middle of last month, a relatively short wait for version upgrades. However, it’s not clear how long updates will take for the Droid or any other Android handset not manufactured in partnership with Google.

According to Engadget’s source, the phone will initially be available by “invitation only.”  It looks like Google will be deciding who gets invites (hey, Google, call me), but the specifications also indicate that T-Mobile will be able to sell the phone directly to the customers in the future.

The Breakdown

- 512MB RAM, 512MB ROM, included 4GB microSD card, expandable to 32GB

- 5 megapixel camera with LED flash and mechanical autofocus

- 3.7″ WVGA AMOLED screen — in other words, as big as the Droid and brighter

- Worldwide GSM/EDGE, but 3G only on T-Mobile in the US (supports 2100, 1700 and 900 frequencies, meaning Europe should be covered)

- 1GHz Qualcomm chip — if accurate, that would make the Nexus One one of the fastest — if not the fastest — smartphones on the market.

- Wi-Fi A/B//G/N

- Bluetooth 2.1

- GPS

- Accelerometer

The specs look solid, the phone matches or beats every competing Android phone on the market (aside from having no physical keyboard) and also compares quite favorably to the iPhone (faster processor, nicer screen, wireless-N).

The only caveat for potential U.S. buyers is that, barring some sort of firmware upgrade (assuming the 1900 band is just disabled), this phone will only work in 3G in T-Mobile’s network.  If you live in a large city, that might not be a problem, but T-Mobile does have the smallest 3G footprint of any of the major U.S. wireless carriers.

For international users, this is really enticing, because the phone should be compatible with all UMTS bands in Europe, Asia, South America and Australia/New Zealand.

Now all we need is a solid release date and a price.  My friends are ready to buy this sight-unseen.  What about you?  android, Google, nexus oneWhat do you think of the Nexus One?