Lessons in Startup Survival from the Downturn Startups large and small have sprung from downturns. Here's how they've managed.

There may be no bigger emblem of the dot-com bubble burst of the early 2000s than the rise and spectacular fall of Pets.com, hand puppet and all. So why in the heck would someone start an online pet food business in the great recession of 2009-10?

"As an entrepreneur, you just have to 'go for it,'" says Alex Zhardanovsky, the co-founder of PetFlow.com, who launched his online business a year ago (on the back of an existing business, EpicAdvertising.com) and is now cashing in $1.1 million in monthly sales and growing. This summer, PetFlow raised $10 million from Lightspeed Venture Partners to further grow the business.

The pet food "auto-replenishment" site succeeded where other pet sites failed by focusing on basics like lead generation and the logistics of pet food delivery.