Perhaps it has something to do with a male dominated tech industry along with the fact most men have some kind of red/green color blindess... so Blues are simply easier for them to see and work with. That is why Facebook is blue.
This reminds me of the cover of the book Information is Beautiful. It has a wheel that plots cultures vs. associations and fills in the spaces with the colors that go with them. http://ceslava.com/blog/color-culturas-infografa/
Also most people's favorite color is blue http://www.joehallock.com/edu/COM498/preferences.html
In Western Culture blue is associated with: cold | freedom | happiness | intelligence | loyalty | rational | unhappiness
In Japan blue is associated with: cold | life | loyalty | money | peace | rational
I wonder, does that have any implications on what color to choose when I design my website?
Completely unrelated: Women are attracted to men in red http://www.brainmysteries.com/research/Women_attracted_to_me... Examining that would make a great post for the guys at http://blog.okcupid.com