I periodically clean my browser history, but after a while website entries begin to appear in it that I’ve never actually been to. This is a question I get relatively often, and it’s usually nothing to worry about. Of late I’d also call out “Foistware” – the software that often appears on your system unexpectedly after installing something else. It’s possible your browser may simply be doing a good job protecting you.Some of these sites look quite disturbing, and are not sites that I would ever go to. Spyware often works by forcing your browser to go to places you would never go.Foistware in particular often adds toolbars and other software to your system that intercepts what you’re doing and just rudely takes over, sending you to bogus search sites or worse.
Using different techniques, the blockers intercept the requests to create new browser windows and prevent them.
Most modern browsers include pop up blocking technology of some sort.
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.
In particular I’d have you run the tools outlined in How do I remove PUPs, foistware, drive-bys, toolbars, and other annoying things I never wanted?
Many websites employ pop ups – additional browser windows that open up when you visit the site.
These typically contain ads for which the site owner is getting paid.
Pop up blockers were created to prevent pop up windows from happening.
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. History entries certainly don’t have to be created by pop ups alone.