Typically attached to record company puppet strings and found on television and radio speaking of things that you can ONLY obtain, or very simple 3rd grade analogies about them (I'm hotter than the sun).
These rappers are not impressive and you can sometimes predict what their gonna say because of how simple the lyrics are. They are typically uneducated and ironically are the most popular and commercially successful rappers.
However I wouldn't consider EVERY shallow rapper to be naturally like that, MOST of them use to be more creative and deep but had to change due to America's ignorant "dumb it down" demand for music
ANY rapper that sings
MOST shallow rappers became popular because of one song that is a party/dance single
(a rare exception would be Lupe Fiasco)