In popular culture every new business is often called a "startup". Yet to me, the key feature defining a startup in the "Silicon Valley sense" is a capital structure optimized for:

1. growth of equity value as the primary "payday" for the founders

2. receiving investment in exchange for equity based on a similar "payday" for the investors

3. non-linear growth of equity value.

Technology tends to facilitate this organizational optimization, but it can also facilitate business optimized for the generation of regular cash returns to investors.

Agreed, I wonder what people like @pg consider as a startup.

I suspect it has the features I mentioned since I developed my definition by using Hacker News.