Here's the answer that I upvoted and decided to share them with you.
Quora has been a better professional networking platform than LinkedIn since the day it went public. Quora’s nature allows the user to interact both professionally and personally. Catching a glimpse of someone’s “personal nature” on LinkedIn almost never happens.
It’s a very sterile web site largely full of resumes, mission statements and very little personal interaction or even community participation. Their problem is that the community has almost no valid social structures and instead focuses way too heavily on personal promotion…which IMO is tedious and boring. And the atmosphere is so stringent that it intimidates people and actually discourages activity.
There are two main types of people on LinkedIn. The people that spam their ideas or blogs or scams - and the rest that kind of just hang around like spiders. Since Quora’s launch going to LinkedIn for networking almost feels like a chore. Ya, they have more professionals than Quora but they are just profiles. If none of them actually speak then what good is that?
Quora gives us a common ground to find with each other and rewards participation. Quora actually stimulates dialog on personal levels. IMO that is invaluable for networking and the reason I spend 2 minutes a day on LinkedIn and 20 at Quora.
Source -- Is Quora becoming a better place to network professionally than LinkedIn? - Quora