It was created to show the difference between computers that were owned by companies (at one point they were so large and so expensive that only big groups could afford and store them), and the era when computers became small enough for individuals to be able to fit them in their own homes, and also afford them. The era of the Personal Computer (PC) was a huge changing point in history because it brought a lot of power and connectivity into people's homes that hadn't been available before.
The CSS position property defines the position of an element where generally the top, right, bottom, and left properties will determine the position of the element.