All four of the major U.S. mobile carriers, Sprint, Verizon Wireless, T-Mobile, and AT&T Mobility, offer mobile broadband plans. ALL FOUR offer the same 5GB for the same $60/month as their top plan (mobile data access only). Tacit collusion? I’m not saying. I’m just saying.

After it’s first 6 months in the market, T-Mobile’s G1 sold about 1 million devices. AT&T sold 3.7 million iPhones in the first 6 months after its launch. One of the key differences between these launches has been the economy, which has been in a recession for the entire in-market period of the G1 and has definitely hit the telecom industry hard as consumers tighten their wallets. Has the G1 launch been successful?

Let’s do some back-of-the-envelope math.

iPhone launched in June of 2007, and the G1 launched in October of 2008. After 6 months, iPhone accounted for 5.3% of AT&T users (3.7M iPhones / 70.1M AT&T subscribers at the end of 4Q07), while the G1 represented 3.0% of T-Mobile users (1M G1s / 33.2M T-Mobile subscribers at the end of 1Q09).

AT&T added 3.7M iPhones over a period in which they added 6.4M net subscribers (70.1M at end of 4Q07 minus 63.7M at end of 2Q07), for a ratio of 58%. T-Mobile added 1M G1s over a period in which they added 1.1M net subscribers (33.2M at the end of 1Q09 minus 32.1M at the end of 3Q08), for a ratio of 91%. This may indicate that T-Mobile has punched above its weight on the G1 launch.

CAVEAT: Some existing AT&T and T-Mobile subscribers upgraded to the iPhone and G1 and therefore did not become new subscribers. Since this effect applies to both carriers, I’m still using these numbers to calculate a rough measure of the success of each launch relative to growth activity over the same period.

Keep in mind that this speaks nothing to the profitability experienced by either carrier tied to these devices, and that is the ultimate metric. There are many ways to look at the data, but I believe that Android has had a pretty respectable first 6 months, especially given current economic conditions.

There is speculation of up to 9 more Android devices possibly launching this year alone and a new iPhone announcement expected in early Summer, which should continue to keep things interesting.

I’ve been recently exploring the BlackBerry App World, and the free Amazon application is something special. The app has a feature called “Amazon Remembers,” which allows you to take a picture from your phone and upload it. That’s just the beginning.

I tested it by taking a picture of another phone. Two minutes later, I received a message telling me that the item has been identified as the Nokia E71. I am shown the price, product details, reviews, and the option to buy now or add it to my wish list. This is remarkable! Amazon will help me buy an item, and I don’t even have to know what it is!

Killing time in a Barnes & Noble while my laptop was being repaired, I snapped a shot of a book cover that interested me. That book was sitting on top of my Amazon home page as soon as I fired up my newly-fixed computer, seemlessly transitioning my experience to the web. Ironically, they now have Barnes & Noble to thank for that sale.

When I sent them a picture of our cat, I received a product recommendation for “DVD for Cats: While You Are Gone.” No sale, but still an interesting response.

What an excellent use of here-and-now context for a mobile app! Color me impressed.

I recently had the pleasure of meeting a very innovative group out of Boston, called The Echo Nest. They built a “music brain” that scours the internet for information about bands on a massive scale, analyzes musical structures, and pulls it all together into a suite of API tools great for recommendations and music apps.

So I tried out their APIs and created a quick IM Bot that will reply to instant messages containing a band name with a list of 10 “similar artist” recommendations. It’s nothing fancy, but it’s fun to play with: http://developer.echonest.com/showcase/show/15

Add the following buddy to your IM: ** AIM: ChimneyBot ** YahooIM: ChimneyBot ** GTalk: CrookedChimney@bot.im ** Send it any artist name. It will automatically reply with 10 similar artist names.

The mobile services side of my brain wonders how many more innovative applications could be easily implemented on mobile by way of instant messenger. No expensive short codes to setup. No device compatibility to worry about.