Galileo can connect to the Internet using its Ethernet or Wi-Fi adapter. To do so, you've learned how to build and boot the board from a bigger Linux image through an SD card, which uses Wi-Fi drivers and makes sketches persist when the board reboots. Also, you've learned how to execute Linux commands from the Arduino IDE, finding your IP address, and reading the CPU temperature. You used the SD library to be able to collect temperature samples, and finally created a Web Client that is able to plot charts.
In the next chapter, you'll learn how to develop a motion sensing light using the Arduino IDE.