A number of people are wary of the get-rich-quick schemes as they are all scams. Due to this reason and others, most of them want to know if bitcoin has any relationship with Ponzi or pyramid schemes. These schemes require recruiting people to recruit others and there are rewards for you as others are recruited.
There is a need for ranking in Ponzi schemes which do not occur with bitcoin as operates using the blockchain technology which does not require any sort of rank. Bitcoin does not have any relationship with any of these schemes. Bitcoin is a currency just like the US dollar and although these currencies can be used for these schemes, Bitcoin itself is not a Ponzi scheme.