[sethammons]

They could attempt to sell it back to the organization. I was never happy with my work's solution for url shortening at scale (we wrote more links than bit.ly by a wiiiide margin, and each link would likely only be clicked a few times at most). Talking with the cofounder, he said, "you know, if someone (cough, you, cough) was really smart, they would solve this and then work to be bought out by us." I didn't have the risk tolerance at the time.

[bodangly]

This is quite risky though. It’s very possible they would be in violation of their employment contract, or run afoul of the law in some way. Questions like did they steal the idea, did they use any company resources or time, etc.