At the time of writing this post the video has been viewed 1.7 million times.
BBC News Online notes that the video is #1 on UK iTunes chart and #2 on the US iTunes chart. Day reports on her blog that it has also reached #1 on the Amazon chart.
ETA: The song has become a freaking earworm. Gah.
Jill Peterson and Kevin Heinz were married on 20 June 2009 in St Paul, Minnesota. The video of the procession was uploaded to YouTube for the benefit of family and friends on 19 July. It quickly went viral: