On 8th of December, Tom Lane committed patch: Support automatically-updatable views. This patch makes "simple" views automatically updatable, without the need to create either INSTEAD OF triggers or INSTEAD rules. "Simple" views are those classified as updatable according to SQL-92 rules. The ...

Every now and then there is someone on IRC, mailing lists, or private contact which asks about rules. My answer virtually always is: don't use rules. If you think that they solve your problem, think again. Why?