Microsoft's Bing search engine is banning advertisements from companies that offer third party tech support for its Windows operating system, and occasionally for Apple OS X, because most of them are scams.

"Bing Ads disallows the promotion of third party online technical support services to consumers because of serious quality issues that can impact end user safety," according to a statement.

These scams are a growing industry on in the murky sidelines of the internet, bombarding users with ads claiming their systems are broken or malfunctioning in some way.  Sales reps then charge the users extortionate fees to "repair" their machines - which they have have actually made worse by installing malware.  Most of these scams collects victims by advertising in online search engines, buying up ads that are triggered by tech support buzzwords entered into the search bar.

Microsoft's crackdown comes a few days after Google announced that it would take measures to protect consumers from exploitative advertisers, banning ads from payday loan companies as of 13 July.  Facebook already bans payday loan advertising on its site.