Perhaps almost anyone can be a photographer, in the same way that almost anyone can be a carpenter or a librarian. But, in age where almost everyone owns a camera, what separates one's work from others. I think our work is separated because we have chosen Photography as our profession, and merely that. Whether we are good or bad photographers, we are photographers because that is what we want to do for a living. We normally don't call ourselves carpenters just because we build a single shelf. It is only if we continually work and strive towards carpentry, do we then call ourselves a carpenter. I feel it is the same with photography.
One may also say that what makes us photographers is that we intend to have our work viewed beyond the context of our friends and family. It seems that photographers wish to have their work seen in galleries, films, schools, websites, and other areas where we may find displayed art. This is certainly not true in every case, although I think it is most generally found to be true.