The truly innovative startups, the ones every investor wishes they were in on the ground floor of (Google, FB, Twitter, ...) could not have been summarized as "the X of Y" before their introduction.

Meh. Google was "yahoo search but simpler/better", FB was "myspace but non-customisable". Twitter is arguably more innovative, but could be summarised as "the texting of internetz".

Do any of those descriptions really do a good job at selling? If I heard any of those back in the day, I would have said "so what?" The answer to that so-what should be the pitch.

While I agree every start-up should be able to summarise their business in a single sentence, this isn't always possible. As the article points out it can encourage the use of vague buzzwords tip-toeing around the actual workings of the company and leaving people still without a clue as to what the company actually does.

And sometimes a business simply can't be summarised to such a short length, after all you want the listener to gain a quick, yet good understanding of what your start-up does. Keeping it short could lead to leaving out critical information though.

That said, I'll certainly work on single sentence descriptions for my projects, it can only be a credit to your business if you can have the listener instantly know what you do in a matter of seconds.