Google has launched a new website called Android Design. Android Design will help developers learn about the principles and building patterns related to apps. If you are not satisfied with what is on the website right now, Google will continue to add more in-depth content in the coming months. [Android Developers Blog]

The Google Android Market has surpassed 400,000 applications.  That means that 100,000 apps have been added between now and August 2011 and 200,000 more since April 2011.  Of these 400,000 applications, about 2/3 are available for free in the Android Market.  The percentage of free apps has grown month-over-month from 60% in April 2011 to 68% around the end of 2011.  Now there are about 100,000 publishers that are active in the application store. [Distimo]

YouTube has been able to capitalize on music videos that have been uploaded to the website in a couple of ways. Advertising is the primary source of revenue and the other way was by providing affiliate links to AmazonMP3 and iTunes. Today when I was watching this music video was the first time I noticed a link to the Android Market music store. In the design, it looks like AmazonMP3 and iTunes have been placed in on the next line using a
tag. Google launched Google Music last month with EMI, Sony, and Universal on-board.

Facebook has updated their application for Android. Now it is easier and quicker to browse through photos and navigate. Photo albums are twice as fast as the previous Android app. Messages and notifications are now at the top of the screen so you can respond to people without leaving the page you are on. The menu has been moved to the left so you can quickly access News Feed, Groups, Games, and apps. [Facebook Blog]

Google Inc. (NASDAQ:GOOG) has just announced a HUGE milestone. The company has hit 10 billion Android Market app downloads. In the same blog post, Google said that Android users are downloading about 1 billion apps per month. To celebrate this milestone, Google is lowering the price of some of their top apps to 10 cents each for 10 days including Asphalt 6 HD, Color & Draw for Kids, Endomondo Sports Tracker Pro, Fieldrunners HD, Great Little War Game, Minecraft, Paper Camera, Sketchbook Mobile, Soundhound Infinity, and Swiftkey X. [Android Developers Blog]

Twitter has updated the Twitter for Android app, with notable additions of push notifications and the ability to simultaneously run multiple accounts. The update is available in the Android Market. What the Twitter Blog announcement doesn’t mention is the sleek new UI of the updated app, which is even more intuitive and easier to use than before. [Mashable]

Twitter has added push notifications and multiple account support to their Android application. These are two of the company’s most requested features.

WhitePages has launched their new Localicious app in the Android Market instead of in the iPhone App Store because the company is dissatisfied with Apple’s slow app approval process. All Things D reports that iPhones are the target market for WhitePages, but that Chief Operating Officer Kevin Nakao has found that Apple holds apps “hostage” and doesn’t always allow apps the access they need. Currently, launching with Android instead of Apple means a company has better information and resources to plan the timing of a launch.