Everyone is a possible expert, but the leader board shows the top "earners" of the title expert.
Quote from the link you linked:
The leader board recognises the top experts for the current week, and the top experts of all time. There's also a leader board for each topic, to recognise experts in specific fields.
Background When you hear the words ‘Release notes’, almost always you think of an unsolicited email from a software vendor. But I am here to tell you that from our data, sending release notes via E...
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