2) I have not applied to YC, and do not have plans to do so in the immediate future. (Never say never.) Nothing personal: I love what YC does, but to make the deal mutually beneficial, I'd have to take outside investment in my business, swing for the fences, and achieve an exit in the next few years. These do not match my personal vision for the next few years of my life.
3) My feelings on outside investment: I have had a relationship before where somebody could call me and berate me for the lack of progress in my projects. He was my boss. At least he had the decency to pay me money every month. I do not fancy having a relationship in which someone can call me up to berate me for my lack of progress and then say, at the end of the call, "Don't forget, we want you to pay us lots of money!"
4) http://www.bingocardcreator.com and more projects early in the pipeline