I really can't get the point why I was awarded the "quorum" badge. What does the "quorum" badge represent? Any suggestion..
a gathering of the minimal number of members of an organization to conduct business
quorum (plural quorums)
The minimum number of members required for a group to officially conduct business and to cast binding votes, often but not necessarily a majority or supermajority.
"We can discuss the issue tonight, but cannot vote until we have a quorum."
Check out the https://meta.stackoverflow.com/faq , and even in the Stack Overflow FAQ proper it says
If you want to talk about the site itself, please don't do it here. Visit our meta-discussion site where you can talk about things like what questions are appropriate, what tags we should use, suggest a feature, or generally discuss how Stack Overflow works.
The description is pretty clear:
"One post with score of 2 on meta"
where meta is the meta site of that specific Stack Exchange site.
Additionally, there's a silver version of that badge named "Convention" which is defined to be:
"10 posts with score of 2 on meta"