At first I wondered why Skittles would air a US ad that is a couple of years old, and then I thought about it a bit more. The popularity of the ad online has acted like post-production research, gathering feedback and word of mouth spread.
Instead of risking budget on a new ad campaign, why not take something we know people in the UK like; but has never been shown on their TV screens?
Maybe this is the next level of using online video as campaign research; producing an ad, placing it online then using the success or failure to determine whether it is suitable for paid media spend. In theory this would allow brands to take more risks and produce more interesting work; because if it bombs it will never have any money other than production put behind it.
You might ask how this is different to now, and the answer is simple. Most agencies currently either:
Make a TV ad - run it on TV and place it online.
Make an online video - spread it online
What I am talking about is making TV ads, but taking them online first; surely a much more reliable test than showing it to 8 people in a room?