What’s that funny square thingy on the left of the page all about?

The funny block in the sidebar is called a QR Code.

A QR code (abbreviated from Quick Response code) is a type of matrix barcode (or two-dimensional code) first designed for the automotive industry. More recently, the system has become popular outside of the industry due to its fast readability and comparatively large storage capacity. The code consists of black modules arranged in a square pattern on a white background. The information encoded can be made up of any kind of data (e.g., binary, alphanumeric, or Kanji symbols).

Scan the code using your smartphone and it will bring that page up on a mobile device for later reading.