Co-founder of four, data-driven tech companies: iQuiri (Aquired '03), NCB Data Services (Aquired '06), Pharos Global Strategies (Purchased '09), Trulioo (Currently post-Series B).
I built four companies with the same co-founder. I know what it takes to make it work, the pitfalls and the tips and tricks. If you need, have or don't any longer want a Co-Founder, I will be happy to give you some guidance based on my experience and the experience from others that I have have met. I am currently researching and interviewing partners in all industries for my book and growth program.
You will always be a Founder or Co-Founder and your title will change. Be sure to be careful however how you dole out the Founder/Co-Founder titles. That should be a lifetime title so be sure it goes to the right people who played a major role in the starting of the company and who will continue to play a role in the years to come. Another option is to give yourself the title President if you have plans to find someone to run your business (say if you are a technical founder)
