Is Groupon really a tech startup? Why? Because it uses email? Because it uses an algorithm to trigger a deal's tipping point?

The lines are especially blurry in New York, where media, ecommerce and fashion are the strongest markets. Angel investor Mark Birch mused on the topic this morning. "Technology is required, but it is certainly not the differentiator," he wrote. "And do not expect the winners to be based on the best tech. It will come down to execution, closing deals, smart user acquisition strategies, and superior service/community." Sounds like Silicon Alley's specialty.

One thing does seem to be held in common across the range of new tech startups: scalability. This may be why some tech VCs are investing in more mixed-blood startups. If the business can scale with the speed of Facebook, Tumblr or Pinterest, it seems to be fair game—whether it's eyeglasses, custom pants or Internet-enabled grilled cheese.