In early days Quora was place where smart people ask smart questions and it has been place where you could reach people of great importance and ask them questions. I really enjoyed service until demographic change in last few months, when quality of service declined. We have seen this before, as you expand and get on ubiquity, you loose on quality of service.
In early days, Quora superstar investors ( like Matt Cohler from Benchmark Capital) introduced service to important Valley people. And they loved it. Important people attracted more insightful users and so on. Those where days of Quora "renesance".
Current state of Quora is best described with "Veine" diagram from above. Reaching out more and more people, Quora will gradually shift towards right and closer to quality of Yahoo answers. It is price of success. But, we can learn important lesson here of success of startups. Invetors and early adopters CAN make huge difference.
If you are user of service you can find me on if you serch for Bojan Babic.