- [Listen and notify](http://www.postgresql.org/docs/9.3/static/sql-notify.html)
- [hstore](http://www.postgresql.org/docs/9.3/static/hstore.html)
- [Recursive Common Table Expressions (CTE)](http://www.postgresql.org/docs/9.3/static/queries-with.html)
- [Full text search](http://www.postgresql.org/docs/9.3/static/textsearch.html)
- [JSON and other data types](http://clarkdave.net/2013/06/what-can-you-do-with-postgresql-and-json/)
- [GIST and KNN](http://wiki.postgresql.org/wiki/What%27s_new_in_PostgreSQL_9.1#K-Nearest-Neighbor_Indexing)
- [Javascript - plv8js](https://code.google.com/p/plv8js/)
- [Python](http://www.postgresql.org/docs/9.1/static/plpython-funcs.html)
- [More reasons…](http://www.ashnik.com/25-features-your-developers-are-missing-when-not-using-postgres/)