I believe it was made clear that their last raise will be the final round they will take so whatever they do will need to make the business sustainable in the long run. My guess is by participating in YC, they can:

- Find up-and-coming businesses that are tangentially related to Quora's mission that they can groom and perhaps invest in.

- Incubate within the YC ecosystem some spin-off businesses that may not fit well under the Quora brand and what they're doing.