A recent post on the Chrome blog discusses Google’s recent efforts to clean up the growing problem of ad injection on the web.

From the post: “Ad injectors are programs that insert new ads, or replace existing ones, into the pages you visit while browsing the web.” If you’re seeing a lot of advertising on all the sites you visit, and much of it seems unrelated to the site, your computer may be running one or more ad injectors.

Ad injectors are unwanted software that is surreptitiously installed on victims’ computers through a variety of tricks, including “marketing, bundling applications with popular downloads, outright malware distribution, and large social advertising campaigns.”

The ad injection ‘ecosystem’ is complex, and at any given time there are thousands of injection campaigns affecting web surfers.

To combat this problem, Google has identified and removed 192 apps – identified as contributing to ad injection systems – from the Chrome Web Store. Improvements in the Chrome Web Store and Chrome itself help to protect against ad injection software. And Google is reaching out to advertising networks, to assist them in eliminating ad injection. Most importantly, Google’s AdWords network policies have been tweaked, to make it more difficult for the perpetrators of ad injection schemes to promote malicious software.