A really nice use of Snapchat - on 4th October Asos sent about 10 different discount codes to their followers. You had to write the codes down quickly (or - um - take screengrabs like I did) because they disappeared after ten seconds.
Asos are 'asosfashion' on Snapchat - follow them for more
Er, hello @Snapchat! Yeah, we’re totally on there… and we have some secrets to spill. Get following ‘ASOSFashion'
— ASOS (@ASOS) July 3, 2013