[DrScump]

  More to the point, this "killer feature" is easily cloned by a competitor

... which is why I was skeptical of Groupon's value from the outset.

[beager]

And much has been written of that, and that's exactly the same way I feel about Uber.

(And every time I mention that about Uber on HN, people point out that they can get Uber in any city in the world, so why would anyone who never travels use anything else?)