OOT-Does PostgreSQL has commercial level.

I reads from some hand-book, about PostgreSQL
and i found something make me confusing. It's
about the Commercial-Level. I've been thinking
that PostgreSQL is a Completely-Free. So if
there is a Commercial-Level, Could anybody
gimme some explanation about the commercial
level. Are there any special-things about that..??

Thank's and GOD Bless You All.

Yudha Setiawan.
VoIP
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