On November 5, 2007, the Open Handset Alliance, a consortium of technology companies including Google, device manufacturers such as HTC, Motorola And Samsung, wireless carriers such as Sprint and T-Mobile, and chipset makers such as Qualcomm and Texas Instruments, unveiled itself, with a goal to develop "the first truly open and comprehensive platform for mobile devices". The first commercially available smartphone running Android was the HTC Dream, also known as T-Mobile G1, announced on September 23, 2008.
Android has many birthdays or anniversaries. Some say it's the day that the Android SDK was dropped. Some say it was the day the first commercially available phone was announced. Others prefer the day that phone, the HTC G1/Dream went on sale. This is just one of them.
Android has come a long way in 10 years, and shows no signs of slowing. It's been a wild ride over the past 10 years.
Source : Google