What a great idea!! Who never ask a friend to bring you back a souvenir when they travel to far off lands. When I was younger I would ask my friends to bring me back sand from wherever they traveled to. Then I would display the sand in little pretty bottles that lined my bookshelf. Key chains, I also collected key chains, I still carry about 8 key chains on a key ring with one key.
Anyways if you want to participate in this great swap just head over the her blog and enter.