Posted Sep 11, 2012 4:56 UTC (Tue) by sciurus (subscriber, #58832)
In reply to: Why json by aristedes
Parent article: PostgreSQL 9.2 released
The core type is basically your number 3, but with validation.
"The json data type can be used to store JSON (JavaScript Object Notation) data, as specified in RFC 4627. Such data can also be stored as text, but the json data type has the advantage of checking that each stored value is a valid JSON value."