[pbreit]

I think you're still missing the importance of the cofounder. It's to demonstrate that you are able to convince at least one single person to join you on the journey. Running a startup is basically one continuous stream of persuasion. Persuading customers. Persuading recruits. Persuading investors. Persuading employees. Persuading investors. Persuading the media. Etc. Etc. Building product, while fun, is easy (in most cases). Being able to persuade lots of people to row your boat in the direction you want is singularly difficult. Until you persuade that one person to join your pursuit, it's extremely difficult to think you have the skills of persuasion necessary to carry out the nearly impossible task of starting a startup.

[aagha]

What if you've already convinced people/companies to buy your product/service? Do you think you still need a co-founder then?