Helping people with computers... one answer at a time.

I periodically clean my browser history, but after a while website entries begin to appear in it that I've never actually been to. Some of these sites look quite disturbing, and are not sites that I would ever go to. Why would these entries appear? Do I have spyware or a virus?

Well, certainly viruses or spyware are a possibility - particularly spyware, which often tries to send you off of to all sorts of places that you'd never want to go to.

But in this case, I suspect something more benign. I think your browser or other tools may simply be doing a good job of protecting you.

As I said, spyware often works by forcing your browser to go to places you would never go. Sometimes it intercepts what you're doing and just rudely takes over, other times it opens a new browser window with whatever it's attempting to push.

Similarly, many websites employ pop ups - additional browser windows that open up when you visit the site. These typically contain ads or other material related to the site. Not infrequently they contain ads or material completely unrelated to the site. The site owner is typically getting paid for this type of advertising, or he's using it to promote more of his own ventures.

"...a URL that's been requested as a pop up may actually get added to your history before the pop up blocker kills it."

And thus we have pop up blockers. Pop up blockers were created to prevent pop up windows from happening. Using different techniques, the blockers intercept the requests to create new browser windows and prevent them. Pop up blockers are available as add on products or software, or they're actually built in to some browsers, such Internet Explorer and Firefox.

Pop up blockers insert themselves into the normal processing of web requests, and "kick in" when they detect that a pop up window is being requested. Exactly where depends on the specific blocker and how it operates. It actually gets fairly complicated, since there are so many different ways to create a pop up window. That's why some blockers are more effective than others.

My theory is simply this: a URL that's been requested to open in a pop up window may actually get added to your history before the pop up blocker kills it. You've never seen it, but it's there in the list.

There are other possibilities as well. Some pages on the web that look like a single page are, in fact, a composite of more than one page. What you see as being a single URL may, in fact, have fetched content from several different sites. Depending on how your browser handles these requests, it's possible that these sub-pages could also show up as individual entries in your history. You wouldn't recognize them, because they're not pages that you explicitly went to.

So, all in all, unless someone else is using your computer when you're not looking, I suspect that it's typically a very benign occurrence. However that shouldn't stop you from taking the appropriate precautions to keep your computer safe.

Article C2624 - April 17, 2006 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

April 22, 2006 10:44 AM

There's one major possibility you didn't address, Leo: just because he doesn't go to "those" kinds of sites doesn't mean other's don't, if others use his computer. Indeed, does he have teens in the house? They could be doing things and going places on his computer that he wouldn't approve of....

August 8, 2007 11:07 AM

After searching for an hour online I finally found this clear explanation of why stuff is appearing in my history when I have never been to these sites. Most of them are porn! I'm glad my pop up blocker is working and I'm not going crazy! Every site online is telling me I'm looking at this stuff when I'm not!

February 11, 2009 12:18 PM

thank you i think its the poker pop ups that are doing this because i click on allmost everything that comes up

May 22, 2009 12:19 PM

Martin: You must stop that nasty habit.

December 14, 2009 10:04 PM

A similar thing has happend to me..I found a bunch of stuff in my web history that I didn't go to. They were all from the same site and in 2 different web history that I have. Porn of this still possible that it is spyware?

March 22, 2010 5:23 AM

So my husband goes on websites like flikr and too shocking and I have found some stuff in the History - but it's hard for me to get mad when i'm unsure if he's actually going on these sites.
How can i tell? is there a tool for this?

Samantha Dolton
June 16, 2010 9:06 PM

This happens quite often to my families cpu also. The culprit in our case is angieslist and craigslist!!!ugh

July 1, 2010 2:51 PM

I've observed the converse, i.e. that some sites that I've been to don't get added to the history. The includes some Ebay pages but the really obvious one is Google. At one time the pages associated with all my Google searches were added to the history. This doesn't happen any more. Is there an option that I don't know about that has been switched?

tamzin lewis
November 28, 2012 11:26 PM

so in my partners phone browser history was a mobidateing.....more than once apparantly browser history rekons the site was visited there was no difference between that link and the other sites he visited ie, colour and of course he denies this and im currently pregnant and find this very upsetting can anyone help and shed some light on this please!!

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