Answer:
The stack just might be sent all over. Full of what's new, yet it's nearly obsolete.
What is lighter than what it is made of?
A precious fluid, thicker than water.
My life can be measured in hours, I serve by being devoured. Thin, I am quick. Fat, I am slow. Wind is my foe.
Without this, eating food and Steven Spielberg's career would be very different.
People take me on walks and I run and have fun. What am I?