Yeah, shoes can really tell a story. I had similar thoughts like you about them, lots of questions, who left them there and why.
I had idea to make photo series about shoes, not abandoned ones, but to use them more as a portrait of personality. We will see how that turns out.
I love your idea about abandoned shoes, I am looking forward to see more photos.
@aprilia thanks for the comment. I'd like to see your shoe portraits. I had a similar idea (great minds think alike) and it was to ask people to be photographed with their favourite outfit (and all their other clothes laid out) to form a picture of someone via their choice of clothing. Your shoe portraits would no doubt be quite powerful.. especially if they were taken in the wearers environment so we glimpse a portion of their lives too !