The difference between the types is described in paragraph two. So, they either benchmarked Postgres while having no idea whatsoever what they were doing, or they were deliberately crippling the competition.
Neither option is confidence inspiring.
(And the first option seems sketchy, seeing how they then went and re-created the whole benchmark as classical RDBMS setup for the second postgres test.)
Postgres' official documentation on json and jsonb is rather concise: http://www.postgresql.org/docs/9.4/static/datatype-json.html
The difference between the types is described in paragraph two. So, they either benchmarked Postgres while having no idea whatsoever what they were doing, or they were deliberately crippling the competition.
Neither option is confidence inspiring.
(And the first option seems sketchy, seeing how they then went and re-created the whole benchmark as classical RDBMS setup for the second postgres test.)