does anyone know what the ps4 does

its very difficult to answer this question because many of us didnt try it,and also there is only few advertiesments about it. i love playstation but its getting weird,why?because i think between ps2 and ps3 there was not many differences,so we were like stupid to buy ps3. so next time i will check ps4 in a store so if it worths buying i will buy hapy mylotting