It may seem good to control all the things your child does for their own safety, but too much control is bad for your child. This is because a child and especially a teen needs to learn self-control. I've seen it over and over when a parent has been too controlling, the child either rebels as a teen or young adult, or they have no idea how to practice self-control when they leave home.
Don't get me wrong, too little control is just as bad. Permissiveness is not good parenting. The best way is a middle road. Your main form of parenting should be listening, teaching, and loving. Then let them learn through their own experience. Give them practice making choices with their electronics, without giving total free reign. For instance, you can have house rules such as computers only in the main area of the house, and no more than one show a day be watched, or 45 min. of computer time. Then you can teach about not watching violence, or pornography. You can fill them with love. Then let them choose, but watch what they do, and discuss their choices and the consequences, but only control what you need to keep them safe...not every little decision. If you clamp down, and don't allow any t.v. or electronics, your child will not have the experience he needs to make good choices in the world of electronics when he leaves home.
When children are younger they will need much more control than when they are teens. Your control should loosen as they get older so they will be able to practice being independent. This doesn't mean you can check out as a parent. You need to know what your kids are doing and be talking to them and teaching them often. You can let them choose how they spend their time, after they have fulfilled their home and school responsibilities. You can teach them that the better they are at fulfilling responsiblities, the more freedom and trust they earn. This is how it works in the real world.
Your goal is to have them be able to take care of themselves when they leave home. Your teaching and your love should not lessen when your children are older. If anything it may need to increase. Don't nag your teens, but pick moments when their guard is down to talk to them about life, mostly listening and guiding them to come up with their own solutions.
The middle road, not too controlling, and not too permissive. Therein lies the "sweet spot" that will help your children grow to successful adults.