Interesting…

How will I make a return on my investment, and when?

Under the terms of our Series B, our (pre-money) valuation is $585M. If we have a successful exit in the future (like an IPO, merger, or acquisition) for more than that amount, you’ll see a return on your investment. Since we’re selling the same class of stock we sold to venture capitalists in our Series B, you’ll get paid out at the same time that they do.

The article sounds like it’s beating the drum for a co-op, but it’s actually a quasi stock offering that only pays out on exit.