Adware is the name that computer professionals give to computer programs that display ads on your computer, or that perform related advertising or marketing functions. In addition to showing you ads, these programs may divert your searches to advertising websites without telling you. Or they may gather your personal information for marketing purposes, also without telling you.
Some advertising programs are benign and open about their purpose. Software vendors or online service providers may offer free or reduced-price versions in turn for showing you ads on your computer. But other advertising or marketing software can be more secretive — and can turn out to be an expensive deal.
Adware that comes from reputable firms is very rarely a problem. It will ask your permission before installing itself, and provide a means for you to remove the ads. (This may mean canceling a service, or upgrading to a paid version. The important thing is that it is your choice.)
But other advertising software can cause problems. This is especially true if it installs itself without your permission. Apart from the inconvenience of seeing ads you did not ask for, it can slow down your computer. If enough hidden programs get onto your computer the reduction in performance can be substantial. You may end up having to pay to have your system professionally cleaned up so that it works properly. Secretive advertising software can be costly in other ways. If it diverts your searches you could end paying more for products and services you buy online. And programs that secretly gather your personal information can be exploited by cybercriminals, with very costly results for the victim.
How can you protect yourself against secretive advertising software? The first step, as for protection against all computer threats, is to be careful. If a deal sounds too good to be true, it probably isn't true — don't click on that link.
But even following good security practices does not provide total protection: You need tools to assist you in protecting your computer. Free virus scan is readily available, and is a helpful start — but it is not enough by itself. Free scans have limited capabilities, and generally do not detect malicious adware.
More complete antivirus protection is not free, but it is well worth the modest cost. And most full antivirus protection tools offer an option to scan for adware as well. Well-designed protection allows you to leave advertising programs that are there by permission, while getting rid of nuisance or dangerous programs that you did not ask for. Which, in turn, will help keep your computer running smoothly and safely.