Why do most social media websites use blue as the main color? e.g., Twitter, Facebook, LinkedIn, foursquare, ...
I am only interested in answers based on some scientific research.
Searching on the web for this I came up with this article.
Quoting from an "Applied Colour Psychology Specialist":
Colour Psychology Blue is the colour of the intellect, the mind, making it the colour of communication and when you think about social media, it’s all about communicating.
Blue also has the perception as being trustworthy, dependable, safe and reliable. These are the perceived positive qualities of a business who chooses blue.
World’s Favourite Colour Research has also shown blue to be the world’s most popular colour.
... read more at the link
Hope this helps
My own research is based on examination of the world around me...
...well - that's not quite how it looks out my window - but that would be lovely.
And that's my point - you only have to look to the skies for the colour blue which is why blue is associated with clarity, optimism, heights, hope, wonder, and calmness.
Blue has been shown in placebo drug trials to be a depressant rather than a stimulant. I can well believe that the calming affect of blue combined with the above characteristics related to the 'sky' effect would result in users having a greater desire to settle in a calm place and therefore staying longer on such a web page rather than the itching-to-move-on that might come with more stimulating colours.
In the above research (British Medical Journal 313 Dec 1996):
In a single blind experiment showing the effect of placebo Blackwell et al asked 100 medical students to participate in an experiment in which they they would receive either a sedative or stimulant drug." All of the 56 students who volunteered in fact received either a blue or a pink placebo. Subjects taking the blue placebos felt less alert (66%) than those taking the pink (26%) and also more drowsy (72% v 37% respectively).
My guess is that it is due to:
Black-on-White has high readability and so does Blue-on-White (Abysoft and Colors on the Web).
Perhaps, Black-on-White gives people a monochrome impression. Therefore, Blue-on-White themes are more used instead. Other reasons, I guess, are the perception of blue in the societal and cultural context.
For details on color blindness, please see colorvisiontesting.com for article.