I believe that greatly depends on how you define the idea. In my definition, the idea for Google was: "Get advertisers to pay for a free information portal." That idea doesn't seem much different to "Advertisers pay for a free newspaper", which was common practice at the time. Similarly, "Advertisers pay for free classified ads" was common, too, but it's how Facebook started out. "Pay for a car ride" = Uber also doesn't seem that new. Or how about "Rent out rooms for money" = AirBnb.

In my opinion, all of those are ideas that aren't really new. But they were executed in a new way and that made all the difference.

HomeAway was already well-known and successful at the time when AirBnb was founded. But the latter reached more potential landlords, due to their specific execution.

I remember using AltaVista for years before I ever heard about Google. So their business idea and business model wasn't new. Their initial execution was incredible, though.

And before I heard of Facebook, I was using MySpace, which was kind of the same basic idea, but pretty badly executed. Until 2 years after the iPhone came out, MySpace was actually larger than Facebook. So my guess would be that it was Facebook's superior execution of their mobile experience that crowned them.