Piracy?

Just skimmed the Guardian UK website and this headline stood out:

Pirates seize oil tanker with UK crew

Just a few weeks ago the US was / may still be involved in monitoring pirates' seizure of a ship near Somalia which had some weapons and parts which should not fall into the wrong hands. Then the link next to it drew my attention.

Live piracy map

That's a lot of virtual pins on the map.

Why is there such a resurgence of piracy? Or is this something that's always been there and is just now getting more press?