Ask HN: When does a startup stop being a startup?

How about on IPO, sale to third party or when the founders give up?

a) When they break even with their original investment and have decent profits for their size

b) When they are considered the leader in their niche

c) When the original founders are no longer at the helm. (Bringing in a CEO for example/IPO)

d) More than 100 employees

But that's just me

Does this mean you don't consider 37signals a startup?

I would agree to no, they are not. They are a leader in their niche (simple small business products) and they are profitable beyond their original investment.

I can't recall how magazine publications refer to them (as a startup or a company based out of Chicago)

http://news.ycombinator.com/item?id=173000

Just being picky but - I think 37signals is a "bootstrap" and not a startup.

37signals is no longer a startup, its a lifestyle business

given that they rely on external funding, I'd say they were a startup.