I came across this video recently. There are many like this, teaching you how to destroy your hair, one style at a time.
It is a massive no-no to back comb your hair. While it does give you volume, it also irreversibly damages the hair. Here is what a normal hair strand looks like.
You will notice that the cuticles are lying flat. This is the ideal position because then it is doing its job of protecting what is lying underneath the hair strand (the cortex and if it is present, the medulla). When hair is backcombed, it raises the cuticles. The inner part of the hair strand is then left unprotected, leaving the fragile inner bits susceptible to environmental pollution, mechanical damage from combing and much more. The cuticles are weakened and will actually drop off easily over time. The Hair strand then looks something like this.
Something to think about if you are on a quest for more volume.