Having been part of a few startups before, I it definately easier to do it with a partner(s). I'm currently doing my latest startup alone - but I dont' consider myself alone. I have two great programmers, even though they are working for me...I treat them like co-founders, we discuss everything not just technical issues, business model and even their love-lives! I'm also getting assistance from my network, people I've worked in the past with and people I've looked up to during my professional career. Each one of these guys have stepped up to mat and offered me guidance each step of the way. Some mentors I talk almost on a daily basis...I treat these guys like board members/quasi-founders also because without their guidance and support I'm sure it would be much harder. Startups are not built alone - they are built by teams...these teams are composed of people who may not be traditionally considered co-founders but I'd argue they are. So I respectively disagree with YCombinator shying away from one person startups - they really need to consider the entire infrastructure. (Sorry for the long post- Chandra)