Best definition I've heard (paraphrased from Steve Blank — http://steveblank.com/2010/01/25/whats-a-startup-first-princ...): a startup is a company that is in search of a viable business model, and is scientifically experimenting with different routes to business success in an iterative fashion, switching ("pivoting") when an experiment gives them data that falsifies their current-best hypothesis for an effective way to make money.

To contrast, a non-startup company has a viable business model, and simply "does what it does," not constantly attempting to reinvent itself as something else.

I assume a company can be a startup even if they haven't yet seen the need to pivot, assuming they're prepared for (maybe expect?) that eventuality? Or are 2 founders in an apartment hacking away at a prototype not a startup until after they've thrown the first one away?

It sounds to me like it's a matter of attitude, rather than size, or business model, or age of the company.

I think the main distinction between startup and a non-startup is how and why they are formed.

Normal businesses that you would not consider a startup usually have only a few people or one person starting them. They usually take some money, from friends/family or an investor or bank. They work hard, long hours. Hell they probably could be in the tech sector. The key difference though is intent.

Normal businesses are looking to build a stable business with a viable income. Usually something akin to a mom and pop store or a restaurant. They tend to be risk averse, and have a business model in mind. Rarely does a normal business start without some sort of revenue source in place.

Startups on the other hand, while sharing a lot of traits with normal businesses, throw risk to the wind and a lot of the times have no revenue model in place (though that does not mean having one makes you a non-startup). Most startups are starting small, and trying to grow big. A lot of the time they are product based, but really startups can be service based just as easily. The main qualifier of a startup is lack of risk aversion and short to long term goals.

There are some edge cases here and there, startups that seem like normal businesses. A company that has a business model, is starting small, and not trying to immediately grow to huge. Some would consider this a normal business, but if the owner feels like it is a startup, then well it is.

A technology company that has a realistic possibility of scaling to something massive (e.g. hundreds of millions of users/revenue).

Why millions of users? Few B2B startup have millions of users.

Likewise it doesn't necessarily need millions in revenue to be successful. Many exits have come from zero revenue.

Revenue OR users.

The question is about what constitutes a startup, not what constitutes success.

I'm going to say a startup is something that can satisfy some formula that takes into account a set of attributes like, size of the company in terms of employees, revenue, age, users, etc... If the result is below some threshold then we call it a 'startup' else maybe it's a corporation..

Now I have no idea what that formula is, but I'm guessing its some calculation that we all do in our head based on our own ideas and in the end we say 'yup.. it's a startup..' or not.

At some point Google, Facebook, LinkedIn, Groupon etc.. all surpassed that level of 'Startup' and moved into the 'Big Company' field.

Can any math geeks out there put together something that reflects that ?

It's really just a buzzword anymore.

I'd say that startup = a relatively new business. Hence the (slightly antiquated) term, "startup business."

A site that doesn't make money (or that doesn't have a business model) isn't a startup business, it's a website (or blog, or forum, or web app, etc.).

I suppose the quest to create a business that works to make money through selling a good or service should suffice. The whole it does not have enough technology associated to it seems to be fairly fuzzy.

A company with a limited operating history that can quickly change their business model. Often, but not required to be, tech oriented with the potential for high growth.

Something that requires (possibly on legal advice) an LLC or similar to go forward?

How about: a small, tech-related business that aims to score big.

Why should tech have anything to do with it? A new coffee shop on the corner is a startup isn't? To me a startup is a new company, that's it, no more, no less.

It just so often seems to have techie connotations in everyday usage. Maybe "tech-savvy" would be better than "tech-related."

Personal def'n = a relatively new company (=< 3yrs).

I like this because it's so simple and easy to measure.