Each key has a tag tied to it which contains a story that has been tweeted to her (so it is no-longer than 140 characters) and she matches a key to a story, then photographs them in a fitting location. Josie explains all of this in a slightly less cumbersome way on the site, so I suggest you go and see.
Anyway, today she published my story and I feel quite proud and happy to see my words written in her beautiful handwriting. I really think the project is one of the best things on the internet right now and to me, it proves that Twitter is several leagues above Facebook when it isn't plagued with general shitty twatness involving X Factor, Radio 1 or Justin "nobodywillcarewhenhisballsdrop" Bieber.
Please feel free to browse the site and if you are on Twitter, why not give Josie a follow and see if you can come up with a story for a key. I'm sure you can.
I realise this post hasn't contained as much swearing as usual, so for those who are feeling a little short-changed, then keep reading...