By making your browser hijacked I refer to either one or some of the following 1) Homepage changed 2) search assistant changed - when you type a url that does not exist, it serves results instead from a "evil" search engine instead of the normal default (MSN or something else if you changed it) 3) I suppose installing unwanted toolbars is part of it too if you like. Here's how spybot S&D puts it "A browser hijacker is a small program or registry setting that is responsible for changed IE start and search pages. If your browser starts with a different start page (one you haven't changed yourself), you most probably got hijacked. Intelligent hijackers do not only change these pages, but also add a small file that will restore the hijacked settings upon each system start. Hijackers often use ActiveX installation programs and/or security holes" Such hijackers can do more then changing your homepage, many create popups etc. It does not include, running software which is adware (eg ICQ) or "tracking cookies". Neither does it include porn dialers that dialup and log up high phone bills.