For
early advertising-supported web sites, banner ads
were sufficient revenue generators, but in the wake of the dot com
crash, prices paid for banner advertising clickthroughs decreased and many
vendors began to investigate more effective advertising methods. Pop-up ads by
their nature are difficult to ignore or overlook, and are claimed to be more
effective than static banner ads. Pop-ups have a much higher click rate than web banner
ads do (about every 14000th popup ad is clicked on).
In the early 2000s, all major web browsers
except Internet Explorer (then the most popular browser
and still as
of 2004) allowed the user to block unwanted pop-ups almost completely. In
2004, Microsoft released Windows XP SP2, which added pop-up blocking to Internet
Explorer. Many users, however, remain unaware of this ability, or else choose
not to use it. Many others are not able to use it at all, as they do not use
Windows XP SP2, but older versions of Windows. Some users install non-Microsoft
ad-blocking software instead. Advertisers continually seek ways to circumvent
such restrictions. Many of the latest pop-ups are created using Flash
and have extensive animation and trickery, others use DHTML to appear in
front of the browser screen.
Pornographic
web sites are among the most common users of pop-up ads. Some particularly
vicious types of pop-up ads (again, most often seen in connection with adult
entertainment sites) appear to have either been programmed improperly or have
been specifically designed to "hijack" a user's Internet session.
These forms of pop-ups sometimes spawn multiple windows, and as each window is
closed by the user it activates code that spawns another window -- sometimes
indefinitely. This is sometimes referred to by users as a "Java
trap", "spam cascade" or "Pop-up Hell" among other
names. Usually the only way to stop this is to close the browser.
Another
variation of pop-up, commonly called "mousetrapping", particularly
fills an entire screen with an ad or Web page, in the process removing any menu
bars or other on-screen icons by which the user can close the window. This problem
mainly affects users of the Windows
version of Internet Explorer. Often, access to other open
windows and Web pages is denied and the only way for PC users to close these ad
windows is via the control-alt-delete command, which can result in
all active IE windows (including those not connected to the pop-up) closing.
Another way to close the mousetrapping window could be to hold down the Alt
button and press F4. This closes the active window. Another variant, a
"static image ad", is a pop-up ad that stays in a fixed position of a
window of an ad-supported program. This kind of ad does not distract the
computer's concentration of a program window like a traditional popup ad does.
One example of an ad-supported program that uses a static image ad is KaZaA.