I'm sorry, but its just not worth expending the extra effort to get you signed up to my service. I can get millions of people before it even starts becoming an issue.
Forcing me to be okay with everyone and their dog seeing what I do on my own time and on a completely different site is unacceptable, and frankly just lazy on their part. That has nothing to do with "commitment." I as a consumer get nothing out of it other than a lack of privacy and the heavy-handed assumption that some startup's "service" outweighs that. No thanks, and the fact that I'm not the only one means that i…
1) It could, potentially, provide some value to you as a user. Quora gets to suggest people to follow for you based on your Facebook friends, so your experience on there is seeded with relevant information.
2) Nothing you do on the site you signed in with is published to your Facebook profile, without your explicit consent on a dialog box.