A pop-up is any information, which appears on your screen on top of a page you are viewing. A pop-under occurs under the page you are viewing, so watch your tabs for these guys and close them. In the past, pop-up blockers were a feature in the browser or you added these to your search bar to prevent adware and spyware pop-ups. Pages you visited with additional ads required a click to open the ad on the website, now if you simply pass your mouse pointer over the ad, even accidentally, the ad will Pop-up. Currently, the only way to stop this is to keep your fingers off the mouse unless you intend to open an ad on a page you are visiting.
The general browser pop-ups are general messages telling you something you need to know. An example of a general pop-up is, "Now downloading a security update" or "Do not turn off the computer updates are installing" or "Your computer will turn off when the download is complete". These (and similar messages) are benign messages, which come from your browser as a pop-up. Another such pop-up is a message from your security program telling you, "You have a potentially dangerous virus or spyware scan now". General pop-ups are usually important pieces of information.
Messenger service pop-ups are another story and without a pop-up blocker, they will interfere with your web browsing experience. They display advertising based on tracking cookies they or a partner company dropped into your browser to track your interests. For instance, if you spend some time searching for a new car in Internet car sales sites, pop-ups begin appearing, offering new cars. You may begin receiving spam car ads in your email inbox.
To stop these messenger service pop-ups install a pop blocker add-on to your search bar. Activate the Internet Explorer Firewall every time you use Internet Explorer. If you are using Windows XP and have not added the XP service pack 2 do this now. The XP SP2 will block pop-ups by using Internet Explorer pop-up blocker settings and allow only pop-ups from secure websites with https in the URL. Some browsers make these messenger service pop-ups are no longer a problem.
Adware and spyware generated pop-up ads function like general browser pop-ups but with a dangerous side effect. These stem from malware and appear to be browser helpers, which are really Active-X controls, which attach to Internet Explorer and export personal and private information back to the person who sent the malware. If a website says: "Activate your ActiveX controls", you should be very careful with that web site (casino sites are known to ask for this for legitimate reasons, but it is too much of a risk to "activate" Active-X by all means.
