We own an Internet cafe shop. I want to know if this business is ok to run. Most of the people use the computers/internet for useful things, but some times we get some people who might use it for things that are Haram. We try our best to monitor the people that use the facility and stop any one who is doing things that are not allowed, but at the same time when the shop is busy you might not see what every one is doing. I want to know if we are accountable for this.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. You have to undertake certain measures to keep an eye on all the Internet users even if the place (internet cafe) is full to its capacity. It is your duty and obligation towards Allah (SWT). If you can watch over your clients (internet users) and prevent them from misusing the Internet in a way that involves disobedience to Allah, then it is good, but if otherwise you fail to do so, then you have to close the Internet café so as to avoid Allah's punishment. In case you fall short of preventing them, then you become a medium and a helping factor in perpetrating sin and transgression, which Allah strictly forbade through this verse: {…Help you one another in Al-Birr and At-Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression. And fear Allah. Verily, Allah is Severe in punishment.}[5:2]. Allah knows best.