Does a Muslim's entry into pornographic websites count as an ongoing sin, the burden of which follows him until the Day of Judgment if he dies before sincere repentance, due to what the website earns in terms of ranking and money as a result of this entry?

There is nothing in Islamic law called "continuous sin" (sayyi'ah jariyah). However, whoever calls to an evil or commits a sin and people follow his example, then he bears the burden of his sin and the sin of those who followed him. This applies to those who created pornographic websites or embellished them and called people to them. If he repents and strives to remove the traces of his sins to the best of his ability, then he has fulfilled his obligation.