I was researching this in a lazy way. Calling the Witnesses a "cult" is not true academically. I do believe it describes a high control religion, however. Cult has a negative connotation. Clicking links on wikipedia for Mormons and Jehovah's Witnesses, I ended up at an article called "New Religous Movements" which describes Witnesses, Mormon, Christian Scientists. Excuse formatting. Quite a few American religions which have beliefs in stark contrast to mainstream religions were formed during the same time period. I forget the full description.
There was a list of four to five items that describe these once new religions. I believe disdain for previous authority is one. Also, I've read a small bit concerning religious developments in America. These groups also have beliefs typical of America and not other cultures.
It is not my main area of expertise so I don't recall details. My guess is that academic literature must be full of books and articles describing these movements. If you find a concise one, please post it here.
Religious beliefs tend to run on a spectrum. Economics and political forces play their part so few religions are unique. I once joined a forum and accidently found a Dawn Millenium. There are some active offshoots of Russell's Bible Students. It was a shock to me. The poster kept revealing his family background and eccentric religious beliefs. I wrote to him completely convinced we might have known each other as young Witnesses. The JWs have never claiming Russell as their leader. Of course, Russell will soon disappear.
Altho the Witnesses kept many Russell doctrines, my family told me the culture was very different. Rutherford transformed it. I've met Mormon specialists going to the opera. Some historians love researching obscure things.