Lets face Russell was a fanatic* as a kid. Had good business sense own a bunch of clothing stores and turned his hand at printing his fanatical ideas. They cleverly were designed around religious issues and gave him power of his readers mind, you the theme already: 'listen obey and be blessed'. Thing really took off after his death under the leadership and direct Rutherford and and later Knorr with kooky Franz by his side. They all capitalized on armageddon predictions and getting free labor from the totally brainwashed loyal following who submit themselves to regular indoctrination meeting every week without fail.
Of course the internet seems to be bringing this corporation to it's knees as it's expose's are so hard hitting and internet savy crowd are gettijng enlightened at a much more eccellorated rate now with instant information at your finger tips.