Oh, the hours of my life I have spent talking about white. It's just not as straight forward as one might hope.
To over-simplify the science of it, surfaces that appear black are absorbing the full spectrum of colour (that's why they get so hot on a summer day), while conversely, surfaces that appear white are actually reflecting the full spectrum of colour. For that reason, there are endless possibilities when it comes to the subtleties of white paint. So if you'd like to paint something white, it's always a good idea to visit your paint store and bring home a wide range of white colour chips to compare to any whites that already exist in the context.
White rooms have always been a stand-by in the art and design world; for the light that they bring, and for their ability to let the other elements in the room (texture, shape, colour, pattern) shine through. As far as colour trends go, we seem to travel through cycles that are in reaction to how we are collectively experiencing life, and what kind of feeling would best serve us in our environments. Painting a room white may be a reaction to having lived with strong colours on the walls for a while, or the desire to have a quiet space to retreat to in an otherwise frenetic world.
Benjamin Moore's 2016 Colour of the Year is "Simply White"
Layering your space with different tones of white and off-white can create a timeless and elegant feeling when carefully considered. One thing to be aware of is how introducing a very clean white to a lived-in space can make older elements look "dirty" all of a sudden. When in doubt, rent a colour fan from your local paint store and bring it home so that you can compare the many whites and find the right undertone.
Of course setting up a visit from your local colour consultant is a wise and time-saving option as well ;)