“The Raspberry Pi is a low cost, credit-card sized computer that plugs into a computer monitor or TV, and uses a standard keyboard and mouse.” – raspberrypi.org
We can say that Raspberry Pi is lightweight, low cost, portable computer which is capable of performing every task which is expected from personal computer. Tasks like web browsing, creating documents, gaming, playing high definition video, etc.
Originally Raspberry Pi become more popular in robotics community because of its specifications. Now Raspberry Pi is being used in Researching and it can be used to create great IOT applications like monitoring, automation, security, etc.
Raspberry Pi provides great environment along with interfaces which makes it ideal for all IOT. Features like own OS named Raspbian, runs on Linux kernel, many GPIO pins, multiple wired and wireless connective interface, low power, low cost, etc. which help developers to create their own systems.