Let's see what you think...

Just pay attention to the intros.

http://www.youtube.com/watch?v=8UVNT4wvIGY

http://www.youtube.com/watch?v=2C68nicab4s

I don't find anything similar.

..... intro melodies. The only difference real difference is tempo. Even the cadence is a near match. I'm trying to pull sources to really see how close they are, but no luck...

The first song is just d minor/ C with attendant notes reminiscent of reggae..also a b minor.
Capo on 5th fret is Aminor / g /f.
The second song is not available on mobile..so..
Many songs have the same basic structure. The difference is only in the way its played.

Nick, check this out for a TON of songs that use the same 4 chords, all put into one song:

http://www.youtube.com/watch?v=oOlDewpCfZQ

Those are all well-liked popular songs 'sharing the wealth' of the science in music.

Ha ha four chords? If you want to see what can be done with just four chords try Status Quo - a British rock band that have been going now for many decades. Love em or hate em, they've been going for years.

I like both tunes .Gotye - Somebody That I Used To Know (feat. Kimbra) then Only If by Enya.Enya always had the airy sound to it.They both have the orch synth similar sound in the begining.I like the reggae sound in Gotye's song.I'm not a fan of newer tunes but I do like these.

Hows about Wingy Mannone's 1930 riff which he called the "Tar Paper Stomp"?

http://youtu.be/IFitLjj418w

Sound familiar? Perhaps you are thinking of 1931's "Hot and Anxious".

http://youtu.be/nyfw8gGe33o

Of course, NICE girls were NEVER "Hot and Anxious", but they just might be

http://youtu.be/ZJE-onnw2gM

"In the Mood"

Meanwhile, back in Rhodesia:

http://youtu.be/uI6VqzdelLA

I love Quo. Especially their 70's stuff. On The Level was a classic rock album.

There was a story on the BBC I heard on the World Service in the late 1980's or early 1990's based on some news story, saying that rock and pop music was on the verge of being 'played out'. The idea was that there is only so many chord sequences you can come up with that make a recognizable hit song before they start sounding like other hit songs.

Borrowing and/or stealing tunes has been a tradition forever. For example, many of today's familiar hymn tunes were borrowed or variations from J.S. Bach's collections of Chorales, and many of those Bach had borrowed from popular tunes he had known as a boy. Pop tunes were often borrowed from "classical" literature, and vice versa. I'm Forever Blowing Bubbles, and Chasing Rainbows popular tunes in the player piano (I have several different versions of each on roll) era were borrowed from Chopin and others. Many of the best classical orchestral and chamber works have melody lines taken from popular tunes. It's pretty difficult to compose a good tune that hasn't borrowed from a previous melody line.

Quite common. One of the bands I played in would mash together "R.O.C.K. in the USA", "Cherry Cherry", "What I like about you", "Gloria" and "Wild Thing". Play one verse from each song and jump to the second or 3rd verse of the next one untill we got all the way through them. Turned out to be around 14 minutes of danceable music that always got the bar hopping.

All I know is that Enya is much more cheery to listen to than sullen Gotye. I admit that Gotye is really good but what's with all the cranky music? I mentioned to a coworker the other day that Adele will have to come out with more songs since the radio keeps playing the same four. My coworker responded with....."well, she'll have to break up with someone so she can write more".

The interval between the first and second 'melodic verse' of I Love Lucy and Star Trek themes is the same. Different composers, same arranger/conductor (Wilbur Hatch), same band (Desi Arnaz Orchestra), same soundstage.

I thought Dominic Frontiere did the Star Trek music...
RW

Dominic Frontiere did Outer Limits. On which both Shatner and Nimoy appeared.