My cofounder and I moved from NYC to the Valley to be part of the S2010 YC batch. The time we spent there was incredibly valuable and definitely worth it, even though we knew from the start our company would ultimately be based in NYC.
Doing YC in no way means you have to leave New York for good.
Could you elaborate a bit on what you learned or realized? Was it simply a different vibe or were there more tangible differences that the rest of the world could learn from?
Two things immediately come to mind, one specific and one a bit vague.
Specific: YC gave us an unbelievable network of founders, hackers and investors in the Valley, and that stayed with us even after we moved back to New York. There's absolutely no way we'd have as strong a west coast (or even east coast) network if we hadn't done YC.
Vague: Valley culture. YC is in many ways at the center of the Valley and embodies the best it has to offer. I don't know how to explain it, but there's definitely a different culture at YC and in the Valley in general than in New York or anywhere else I've been.
It's hard to quantify or describe concisely, because it's really the sum total of people's attitudes, and the conversations you overhear on the street, and the density of people who have built or are building startups, and a thousand other things.
The only analogy I can think of is traveling to another country. For instance, when I traveled to Europe, it felt extraordinarily different from the US, and the differences weren't always easy to pintpoint.
Doing YC in no way means you have to leave New York for good.