Night time the human eye sees blue more readily than red. The opposite is true in that in the day red is easier to see than the blue...
So, I guess if you have a dark background you need to use blue and if you have a light background you need to use red to attract the most attention. Don't pay any attention to that old boring black on a white background.
Colours can invoke feelings and designers play on that, but most ignore all those other meanings that are posted all over the internet. If you were to go by that, you'd be afraid to use most colours for fear of upsetting someone. It's silly. You might want to be careful on the use of red though. For instance, I designed an aviation safety report once. I specifically avoided red because of the industry. Red can signify danger, and you don't want to invoke those kind of feelings around aviation and safety.
Blue is neutral, calm and easy on the eyes. It will look good in the background against other media. That's why a lot of sites opt to use it. Basically, it's safe.