If we're talking about mainstream artists, then absolutely. Videos will always do something, whether it be massive (Bad Romance, We Found Love) or just moderate (Hold It Against Me, Part Of Me).
As someone said, it takes a video to see the song in a different light and that happened with both of my examples of a massive turnout. Hated "BR" with a passion until the epic video. Same with "We Found Love". I had barely played it 10 times until the video came out, now it's with over 300.
(That number was enhanced by Amazon MP3's decision to sell the set for 99-cents for two days during its first week. Billboard has estimated that Amazon MP3's 99-cent version resulted in 440,000 copies sold.)
A bad video won't take away from a singles success, but a good one can make a single more successful. Most of the time it gives people the artist perspective on the song an something to think about whenever they listen to it.
What you do today is important because you are exchanging a whole day of your life for it. When tomorrow comes, this day will be gone forever; and in its place will be something that you had left behind... let it be something good.
Depends in most cases. You just have to strike while the iron is hot.
For example -- videos for WFL and LFN (TGIF) definitely benefited from digital sales. WFL went to #1 on the charts after the video release, and LFN (TGIF) shot from #31 to #4 because of its sales. They were singles that were just starting off and steadily gaining in airplay and sales.
But most times, some artists/record labels don't strike the iron is hot -- i.e. waiting until a song has peaked (when it clearly could have gone on to a better peak). For example, if a song is stuck at #11-13 on iTunes for a while, a video could send the song into the top ten on iTunes, and most songs usually receive a hefty boost in sales when entering the top ten. Maybe record labels/artists aren't too aware of this like we are (since we usually study the charts more than they do ), but I'm sure if they knew that, they'd take advantage of it.
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