Adware is software that displays unwanted advertising, such as pop-ups, banners or ads injected into web pages. It often arrives bundled with free applications or as a browser extension, and it may collect browsing data to target the ads.
Why it matters
At best adware is an annoyance that slows a device and clutters pages. At worst it tracks activity, redirects searches, hijacks the browser home page or opens the door for more harmful software. For site owners it also matters because injected ads can alter how pages appear to visitors, and users may blame the site for them.
Example
A visitor installs a free video converter. During setup a pre-ticked box adds a "shopping assistant" extension. Afterwards, pages show extra coupon banners that the site never served. Removing the extension and checking the browser's search and home settings clears the problem.
Common misconceptions
- "It is harmless because it only shows ads." Some variants collect data or load further payloads.
- "Only my own site can show my ads." Client-side injection can add content you did not publish.
- "A legitimate ad network is adware." Adware is defined by being unwanted and deceptive in how it was installed.
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