In the battle to attain more ad dollars via impressions, some sites and shareware makers are employing homepage hijackers. Homepage hijackers reset Explorer's startup page. Every time the user launches Explorer, it brings up the hijacker's page, which invariably spawns about a dozen pop up and pop under ads.

At its simplest, a homepage hijacker merely pops up a window that asks the user if he/she wishes to change his/her homepage. If the user clicks the yes button, it resets the URL. This is usually a one-off deal, the user can simply go to Tools | Internet Options | General | Home Page and re-enter the URL.

However, most homepage hijackers are far more devious, installing scripts and code that resets Explorer's home page to the spammer's URL, no matter how many times a user might use Tools | Internet Options | General | Home Page. For example, web pages can secretly install scripts on improperly patched versions of Explorer that keep resetting the home page.

Many shareware and freeware apps you download install EXEs that hijack your home page. They usually do it with your tacit approval. You know how that freeware music stealing program you downloaded pops up that 900 word license agreement in an 6 point font? Well, some place near the bottom, after the heading that says "now that you've read this far, let me tell you about a dream I had", it says "oh yeah you agree to let us install all kinds of EXEs and DLLs that enhance your ecommerce user experience." Translation: your browser will always start on our web page and you can't make it go away!