This cool video
visualisation uses Twitter to plot the journey of travellers over a certain period of time.
The video plots on a map tweets that contain the phrases 'just landed in...' or 'just arrived in...'. A location tool then locates where that Tweet was sent from and matches it to the location that the Tweeter has on his/her profile.
Find out more about how such a video was created and see different time periods on blprnt on Vimeo.