This number is based on users logging in through FB connect only. From the Techcrunch story:
"According to AppData, 20K daily active users and 180K monthly active users log into Quora through Facebook Connect — Bear in mind that this is a small fraction of its total number of users, which Cheever and D’Angelo famously never reveal."
"According to AppData, 20K daily active users and 180K monthly active users log into Quora through Facebook Connect — Bear in mind that this is a small fraction of its total number of users, which Cheever and D’Angelo famously never reveal."