This Fridays Music clip of the week is an old classic, Rick Astley's "Never gonna give you up".
Why this? Simple really, to use it as an illustration of the impact of viral / guerilla marketing.

The phenomenon that is RickRolling came about a few years back and involves internet users being tricked to click on a link that redirects them to this old chestnut, the Rick Astley video.
You then realise that you have been "Rick Rolled".

Why this video has been targetted is a little harder to find out, but to date it has been estimated that at least 18 million US adults alone had seen the rickrolled clip at soem point lately.

Why do we need to pay attention to this kind of carry on? It clearly illustrates the potential for directing traffic anywhere on the web. The old bait and switch trick. It gets used heavily on youtube and can also be used to your advantage in a positive way.
The RickRoll kind of does this in that it mostly tricks people on youtube who are looking for things that they will never find on youtube in the first place, and leaves them with a smile.

A bit of history from Wikipedia:

Rickrolling is an Internet meme typically involving the music video for the 1987 Rick Astley song "Never Gonna Give You Up". The meme is a bait and switch: a person provides a hyperlink that they claim is relevant to the topic at hand, but the link actually takes the user to the Astley video. The link can be masked or obfuscated in some manner so that the user cannot determine the true destination of the link without clicking. When a person clicks on the link and is led to the web page, he or she is said to have been "rickrolled". Rickrolling has extended beyond web links to playing the video or song disruptively in other situations, including public places; this culminated when Astley and the song made a surprise appearance in the 2008 Macy's Thanksgiving Day Parade, a televised event with tens of millions of viewers.

Astley recorded "Never Gonna Give You Up" on his 1987 album Whenever You Need Somebody. The song, his solo debut single, was a number one hit on several international charts, including the Billboard Hot 100, Hot Adult Contemporary Tracks and UK Singles Chart. As a means of promoting the song, it was also made into Astley's first music video, which features him performing the song while dancing.

The practice itself is said to have begun as a variant of an earlier prank from the imageboard 4chan known as duckrolling, in which a link to somewhere (such as a specific picture or news item) would instead lead to a thread or site containing an edited picture of a duck with wheels. The user at that point is said to have been "duckrolled".

The first known instance of rickroll occurred in May 2007 on 4chan's video game board, where a link to the Rick Astley video was claimed to be a mirror of the first trailer for Grand Theft Auto IV (which was unavailable due to heavy traffic). The joke was confined to 4chan for a very brief period.

By May 2008, the coverage in the mainstream media. An April 2008 poll by SurveyUSA estimated that at least 18 million American adults had been rickrolled. In September 2009, Wired magazine published a guide to modern hoaxes which listed rickrolling as one of the better known beginner-level hoaxes, alongside the fake e-mail chain letter.

The original video on YouTube used for rickrolling was removed for terms of use violations in February 2010 but was put back up within a day.