mallyh - "i've listened to both versions ,ok the beats the same but that's all i could work out ."
A lot more than the beats are the same.
Plaigarism in music is not just about the structure - if it was, every single blues song would be a rip-off of Dust My Broom because the chord changes are the same, only the tempos and keys vary.
The essence of the song, the vibe, the atmosphere, is what makes it unique, and that is what has been copied. The tempo, the feel, the falsetto vocal, the structure of the rhythm instruments, it all adds up to make Blurred Lines too similar to Got To Give It Up.
If you check out the original thread which Stephen_G has copied in this OP, you will find a mash-up I posted of the two songs layered over each other - that is where homage and duplication cross the line - hence the case, and hence the decision.