Many samples of (working and effective )online partnerships are in world of open source where many hackers around the world are working on much more complex problems than those backed by YC.
My co-founder and I met online working on an Open Source project together, but we certainly aren't strangers who met just to start a company. We'd been working together for years, but had only met in person once before starting the company (and twice before applying to YC, post-YC we get together weekly and communicate daily via email and bug tracker).
It can definitely work, but I'd suggest working with folks on projects (Open Source or school or whatever) for a while before partnering up. It's hard to know how well you'll mesh and how much they'll hold up their end of the bargain. Make sure you can compromise, even in the face of disagreements. And make sure you trust the others judgment so that you don't have to discuss every little thing. I almost never have discussions with my co-founder about any specific details of implementation. We discuss goals and objectives, and then go back to our respective offices and do the jobs we said we'd do in the way we think is best. If it turns out to be wrong, we'll hash it out, but that's so rare that it's not worth taking the time up front to figure it out on every little detail.
Close to 10% of all newly weds meet online these days. And while it's still too early to know the long-term success rates, early ethnographic studies seem to find little difference between couples who meet online and those who meet in person.[1]
If it works for marriages, why shouldn't it work for entrepreneurs?
If anything, I would expect meeting people online to work out much better than meeting people in person. In real life, people tend to organize themselves into hierarchies and befriend others in a similar position. Whereas online, people organize themselves into networks. And networks seems to be more efficient than hierarchies at everything from social introductions to constructing identity and reputation.
Yeah, there isn't a lot of theory surrounding meeting people through online networks, and it seems excessively easy to get yourself into some serious trouble. But that's just sort of the nature of entrepreneurship in general, and I suspect that at present there's something of an arbitrage opportunity for those willing to figure these things out for themselves.
Couples may meet online, but they usually date a while before getting married.
It would be fine if founders initially met online, but I think they'd want to have been in-person friends for several months before starting a company.
No, that's not what I meant. What kills most startups is that they build something lame-- something users see and think "meh" and click on Back. It's not ability to solve problems that makes the difference, but what problems the founders choose to solve.
Friction between founders is somewhat of a threat to startups, but small in comparison with making something users don't care about.
I'd still worry more about an ad hoc group of founders than one that had been friends for a while, but if I had to choose between an ad hoc group with a kickass project and a group of established friends with nothing, I'd probably choose the first.
The thing is, we rarely see ad hoc groups with kickass projects. I think this is because such groups are less likely to build good things.
The great problem with startups isn't a "problem", because it isn't typically the case that startups fail because they have something go wrong. Startups fail because they don't do enough things right.
Following that, the problem joining with a stranger is not that you don't know their quirks, its that it is difficult to find someone with complementary strengths. However, since we hackers are typically drawn to others similar to ourselves, many of those going to YCombinator with someone they have known for a long time will be similarly disadvantaged despite being acquaintances (they will still be two individuals with similar strengths and weaknesses).
Thus what we really need is for two business types to go to YC together, and two hackers to go to YC together, and form two teams, each with one hacker and one business type. Or, better yet, to forcibly enroll the hackers in business courses and vice versa. :)
It can definitely work, but I'd suggest working with folks on projects (Open Source or school or whatever) for a while before partnering up. It's hard to know how well you'll mesh and how much they'll hold up their end of the bargain. Make sure you can compromise, even in the face of disagreements. And make sure you trust the others judgment so that you don't have to discuss every little thing. I almost never have discussions with my co-founder about any specific details of implementation. We discuss goals and objectives, and then go back to our respective offices and do the jobs we said we'd do in the way we think is best. If it turns out to be wrong, we'll hash it out, but that's so rare that it's not worth taking the time up front to figure it out on every little detail.