He makes some useful contributions on the Internet and sometimes he checks out haraam things, should he stay there or leave?
Question

                I am a small-scale seeker of knowledge and I have some good da’wah activities on the Internet, and I am a supervisor in one of the Islamic medical chat rooms. But sometimes I slip and look on the Internet for things that are haraam whilst I am doing my research, and every time I repent to Allah, I go back to this sin. 

My question is: is it better to give up the Internet altogether, which will include giving up the good things that I do on the Internet, or is it better to treat myself and my heart and try to give up the sin altogether? I am confused between the two choices.
Praise be to Allah.
    The solution may not be to advise you to give up the 
    Internet, because there are also satellite channels and magazines. Yes, you 
    may find in the Internet things that you will not find in the other sources 
    mentioned, but what we are talking about here is the basis for your 
    committing sin and blocking one means will not prevent a person from 
    committing sin. 

    The solution in a case like this is to increase your fear of 
    Allah and your respect of Allah so that this will prevent you from falling 
    into that which Allah has forbidden. 

    You have to remember death a great deal, so that this will 
    motivate you to prepare for it. 

    What you have to do is to treat yourself so that you will 
    stop committing the sin of looking at haraam things wherever the image may 
    be. 

    One of the most beneficial of remedies is hastening to get 
    married if you can do so. The Prophet (blessings and peace of Allah be upon 
    him) said: “O young men, whoever among you can afford it, let him get 
    married, for it is more effective in lowering the gaze and guarding one’s 
    chastity.” Narrated by al-Bukhaari (5065) and Muslim (1400). 

    With regard to whether you should stay on the Internet or 
    not, that is subject to further discussion: 

    (a)If you think it most likely 
    that you will give up the sin of haraam looking altogether by getting off 
    the Internet, then cut off all connection to it, so as to protect yourself 
    and remedy your problem, until you become certain that if you go back to it, 
    you will only take part in what is good in it.

    Concern about reforming yourself should take precedence over 
    your concern about reforming others. 

    (b)If you think it most likely 
    that you will never give up the sin of haraam looking and that you will be 
    distracted by watching garbage on satellite channels, and looking at 
    newspapers and magazines, then our advice to you is to stay on the Internet, 
    on condition that you strive hard to keep away from every haraam thing that 
    can be watched or listened to. We believe that if you limit yourself to 
    visiting helpful and beneficial academic and news websites, and limit 
    yourself to regular appointments in voice chat rooms on Paltalk, where you 
    can offer useful and beneficial material and listen to material that will 
    increase your knowledge and faith, then we believe that you will never find 
    time to go to harmful, bad and haraam sites.

    Hasten immediately to repent sincerely from every sin that 
    you have committed, regret your transgressions against Allah, and resolve 
    firmly not to go back to those sins. Turn to Allah with a pure and sound 
    heart, and ask Him for help and guidance, and to purify you of haraam 
    things. And give thanks for the blessings that Allah has bestowed upon you 
    by using them to do things that your Lord loves and will make Him pleased 
    with you. 

    See also the answer to question number
    20229, which contains useful information on means of lowering the gaze. 

    And Allah knows best.