yasamoka wroteNo it's not an expensive gimmick. It's a marketing term.
The maximum ppi that can be perceived by a human eye is apparently 477ppi.
LG and another company are producing 5" 1080p LCD displays with a density of 440ppi.
Retina is a term that refers to MOST people being unable to distinguish the pixels from a few inches away from the screen, the regular distance that one would look at a phone from. In this case, Retina differs from phone to tablet. iPad 3 has a density of 264ppi, while iPhone 4/4S have a density of 330ppi, and the three are Retina.
On the other hand, the HTC Radar and Sony Xperia S both have a density of 342ppi, but are not labelled as Retina, yet they do qualify for it.
you mean HTC Rezound. And I agree Retina Display is just a marketing term made up by Apple, first started by the iphone 4 with 329ppi and then they announced the 3rd gen ipad with 263 ppi, later on they released the Macbook pro with Retina pushing 220 ppi. all these devices have different ppi yet they are labeled as Retina Displays.
As for Android, since version 4.0 Ice cream Sandwich android native resolution is 1280*720 which is pushing 300+ PPI and sometimes exceeding the 329 PPI desinty of the iphone.