Every so often my mobile phone’s browser will spontaneously open an app store. And apparently it’s a known problem with shady ads abusing the prefix (a.k.a. URI scheme) of links. Typically this prefix is the familiar “http:” or “https:”, but when other, recognized values are used it can open software outside the browser.

One of the earliest such schemes I came across was the “mailto:” form. And when a link is activated it often opens one’s e-mail application to send mail to the address indicated. Early on this was quite useful, and some standards were created for interoperability. Nowadays it has expanded to include non-standard schemes for specific services and applications:

• “steam:” starts the Steam gaming software
• “itms:” opens iTunes Music
• “market:” initiates Google Play’s marketplace

Yet rarely have I found a need for these custom schemes to do something meaningful. Often they serve only to get in the way like podcasts only publishing through iTunes, which I don’t have, or the random ads opening Google Play.