Blacksurfing is saving energy while surfing on the web. This can be done using inverted palette, by applying black background and white text. The color black consumes less watts to display content on CRT monitor as compared to an all white page. So, by applying all black background, the majority of the website is black, this way it save energy. The white color is used for the text, this way it is clearly visible on the black background.
A full white web page uses approximately 74 watts an all black page uses a total of 59 watts.