Ask IH: When is a business idea 'validated'?

This is a really interesting question. First of all, it depends on the definition of "validated", which I'd say means that your idea, market, and timing are good, and thus the only thing standing in between you and success is execution.

I think the whole point of the Lean Startup method is to know whether or not this is true before you waste tons of time executing bad ideas. However, it's more of an endless cycle rather than a single moment in time – you're constantly testing hypotheses that, if true, would justify you taking things to the next level. That doesn't necessarily tell you how things will end up long-term (several levels into the future).

For example, there are plenty of businesses that have hit a wall at 10 customers (or ramen profitability) and stopped growing. There are plenty of businesses that signed up hundreds of customers early on, only to see them all churn a few months later because their product wasn't sticky. There are plenty of businesses that crushed it for a year or two and then suddenly became obsolete.

So I don't know, maybe it's impossible to say your idea is validated? The best you can do is form some goals and hypotheses for reaching the next level, then try to hit them, then evaluate what happens and make new plans.

I'd say it depends on the nature of the idea.

For example, for my crowdsourced events app (http://eventradr.com) I consider the idea validated when users come back to create their events without me having to tell them about the site again. So far this has happened very few times. I'll consider the business idea validated when someone finds it worthy to pay to have their event featured on the top of the trending page.