I'm sorry to hear that this has happened and this is a sensitive matter, I thought it would be better to have a man's view of this situation, so I shared your problem with my husband and a few other guys and they all agree that this is a problem.  They felt that an 8 year old child was not mature enough and even wondered why he has such a curiosity at this age.  They said that even though "boys will be boys", this would be a matter of concern even for a young teen.

First, your son should not have had free access to a computer without supervision, even at best when doing a simple google search, you may end up on a site that just didn't fit really what you were searching for, and even myself have had a few surprises.  While searching for a recommended resort at a beach, when I googled the resort, I ended up at porn site, after rechecking, I found that the names were the same, just spelled slightly different,  so it is recommended for children to have supervision while on the internet to help to prevent these accidents.  It is the parent's responsibility for what a child does on the internet.  Next, the uncle needs to be a little more responsible with his personal belongings.

It sounds like you've handled the situation appropriately each time, by remaining calm.  He may feel embarrassed to discuss this issue with you, so you may want to get someone that he would feel comfortable with to discuss this with him, such as the uncle.

I'm not sure that you have reason to worry, but you do have reason to get involved and prevent these things from happening. Here are some sites that may help you and your son.  At very least, minor porn can hamper your child's maturity and may even "set the stage" for him to become "the victim".  I would not dismiss this, I would take action now, and keep in mind, that it may be too late to simply remove his source, he knows what is available and may seek new ways to satisfy his curiosity.  You may even want to consult a professional to discuss this matter further.

Best wishes!

Although interest in nudity can be normal, an 8-year-old boy should not know what sex games are.  

First of all, I would recommend that you put blocks on the internet, if you have not done so already, so that he cannot access inappropriate materials.

Second, interest in nudity at this age can be healthy, but if it becomes more intense or inappropriate, you might want to explore the reasons asap.  

Third, have you noticed any behavioral changes in your son?  Has he become withdrawn, sad, angry, gets mood swings?  If so, you may want to address this with a pediatric counselor as soon as possible.

Suggested readings:

Is interest in nudity normal?

http://www.pluggedinparents.com/component/content/article/531

Best regards.

Ok i know kids are curious but this is not  normal  act for a 8 year old, their has  to be more to this, as for where he start to do this, did some one put him up to this.. get some professional help for children.. you have to get to bottom of this... before it gets worse ... if you feel that you need the help go for it ... remember your the parent and have the right seek help///..

Hello. How are you. You have every right to be concerned. It usually starts off with a little and if it doesn't get checked now it will be a disaster. There is a solution. You do need to take away any kinds of electrical device that would give him access to porn and magazines. I don't know if you have a relationship with God, but he will direct you by way of His holy inspired writings, the Bible. I do hope and pray that you follow my advice and let your son know that he will have to give an account for his life when he stands before Jesus the Son of God. Ask God to direct you to a local church body, if you're not already part of one that teaches the truth. Your job is to train up your child in the way you would have him to go so that when he is old he will not depart from it. If you would like to know more about the only (solution), you can email me at marylcooper86@yahoo.com.I will be praying for you. God Bless.