Apps on Google’s (GOOG) Android platform are surging with ‘roids from the boom in Android phones, too.

Google’s Android juggernaut continued through the last financial quarter and was picking up steam, Google reported in its earning report Thursday.

More than 3 billion Android apps have been installed, with downloads up 50 percent from Q4 2010.

Leena Rao said in TechCrunch: “(T)hanks to the fast growth of the sale of Android phones, Google’s app downloads are growing fast. The first billion installs took 20 months, the second billion installs took another 5 months, and the third billion took only 2 months.”Four billion won’t be far off.

Electronista said the download figures are believed to include all stores and not just the Android Market.

Electronista staff said: “While the app install count was a significant milestone, it shows Android continuing to trail in app use relative to iOS. Apple (AAPL) reached 10 billion App Store downloads in January, or more than triple the size despite the App Store only opening three months before Android arrived. Apple’s longer investment in tablets and its encouragement of non-phone devices like the iPod may have played a part, though its holding over 350,000 apps versus the estimated 120,000 for Android may have played its own part.”

Each day, 350,00 Android devices are being activated, said Jeff Huber, senior vice president of commerce and local for Google.

Pouring some cold water, Electronista said, “The increase came about five months after reaching 300,000 in December and suggested a minor slowdown.”

Apple has not provided an activation rate since September, when it reached 230,000 iOS device activations per day. Likely the number has increased, with the addition of the Verizon (VZ) iPhone In February.

Google offered no breakdown was given between free vs. paid apps.

The Googlers also repored more than 500,000 advertisers use click-to-call ads, which include a phone number that users can dial directly from the ad.