Android is an open source operating system developed by Google and the Open Handset Alliance. It was originally developed by Android Inc. which was purchased by Google in 2005. The software stack consists of applications, application framework, libraries and runtime, and the Linux kernel. Some key features of Android include an open application model, support for third-party applications, and integration with Google services. While Android provides advantages like customization and a large app selection, it also faces limitations such as inconsistent app designs and unstable performance.