I'm not sure if interpret the message of the book the same way some of you do. But that's OK. Frankl, I thought, was writing about how having meaning in one's life enables the human psyche to endure the hardships of suffering. As he saw time and again in the concentration camps, once that link of meaning was severed (say someone found out their family was no longer alive), the body broke down quickly. In many ways, to sever meaning was a deadly act.
This is far from limited to concentrated camps, though. An example I'm thinking of right now is how women go through an immense amount of suffering to have a baby. To most, having a baby is an intensely meaningful thing, and great joy comes as a result of the suffering.
I think Joseph Campbell said that it's not so much the pursuit of meaning but the desire for the experience of being alive that drives people. I tend to agree with that, however weird it may seem to post on Sanctioned Suicide. Through experience we find meaning, but if we go looking for meaning from the outset it's like going in backwards and we end up overturning rocks looking for an abstract thing that we must cultivate ourselves.