Ask HN: Found cofounder, cant' find idea. What to do?

What do you mean "can't find idea"? If you didn't have an idea, why look for a co-founder? I hope you are not looking to start a startup just because you want to do one.

You should have found an idea before a co-founder. Your co-founder should complement the direction of the business and bring what's missing in your personal skill set.

First step now, is to figure our what each of your strengths is/are, and then create a list of potential ideas that spark each of you, then choose the one that (a) ignites you both, (b) has a realistic revenue model, and (c) can be built without the need for investor capital.

Make sure you choose something that actually has customers you can get to, not something that has revenue potential when you say "If we can just get 1% of the population..."

Lastly, enjoy the journey.

Perhaps I can help you "find" some ideas... they come so easily if one is open to them...

For example, Uber appears to be the end of the taxi business, but it opens up a whole market to developers. You have a beautiful imbalance now, all those taxi drivers and cab companies are heavily incentivized to compete with Uber or lose their companies/jobs.

If there was (and there might be, idk) a platform that allowed all the cab companies to aggregate into an uber-Uber, there's a market for that with known customers. The only obvious issue I see is that in order to make this work, the cab companies would have to give up their fights to block Uber using municipal codes as they are now.

Anywhere you have an imbalance, there's a potential market. The problem is, if you're not on the demand side, your product has the potential of a short lifespan unless it corrects the imbalance.

Google did this with ads, Uber with rides, AirBnB with rooms, tinder with.. well, you know.

Each of these markets had an unseen demand side which each of the companies exploited. Find an unfilled demand and fill it. It doesn't need to be huge, but if it's in the way of someone already moving there, you greatly increase your chances of being acquired.