HBO's logo has looked essentially the same since the 1970s.
One difference is that the early logo had the O overlapping the B and was accompanied by a red, yellow and blue strap.
In the early 1980s, the logo was revised. The old logo and its colored strap was gradually phazed out.
In 1983, HBO introduced a famous intro for feature presentations. In the intro, the camera would pan through a model city before going into space, revealing the HBO logo.
Another well known use of the HBO logo is the "static intro" shown before and after HBO's original productions.