These people left Yahoo less than 3 years after their startups got acquired by Marissa Mayer
A lot of those deals were meant to be "acqui-hires," in which it's done for the skills and talent of the people at the startup, rather than the product itself.
But some of the founders of those startups didn't bother staying too long at Yahoo - like these people who spent less than 3 years there.
In fairness, their turnover can't all be blamed on Yahoo. A lot of founders like to start multiple companies and don't often enjoy corporate environments.