Also, thanks for the Union Square Ventures blog link, I’m not currently following them and I should definitely read it on a more regular basis.  Are there any other VC blogs you would suggest?

Union Square Ventures says “Early stage investing encompasses seed, startup, angel, and first round investing.” which is more specific than my original description, but along the same lines.

Apart from revenue, profitability, or exit strategy (eg. acquisition), I’m not sure what other lines one could draw to objectively make the decision that a company is no longer a startup.

There are numerous companies that have been around for years and have gone through multiple rounds of funding (Pelago and Twitter come to mind) which I would still consider to be startups, even though neither is “early stage”. Conversely, companies like Delicious and Facebook don’t fit the stereotype, because the first was acquired, and despite its lack of profitability, the second is simply too large.

What you say is very interesting.  I’ve heard “early stage company” used to refer to companies that have been startups for awhile and are transitioning to full fledges businesses (revenue), but maybe I’ve been misunderstanding the context.  From what I can tell, there isn’t a good definitive blog post or definition online – but digging around a bit more it looks like VCs blogs refer to early-stage startups as being pre-funding.  Do you have any sources you find particularly helpful?

I’d consider “stealth”, “seed”, “angel-backed”, and “VC-backed” to all be flavors of startups.

I’ll have to do some more research.