Online content blocking is a hot topic thanks to Safari Content Blockers in iOS 9 and the recent news around AdBlock and AdBlock Plus. Now Mozilla is jumping into the issue with a set of guidelines the Firefox-maker will use, and hopes others will adopt, in deciding when and how to apply the banhammer to online content.

Mozilla is proposing three basic principles: content neutrality, transparency and control, and openness.

The first principle means content blocking software should block content based on user needs and not just because it’s a specific type of content. In other words, if an ad isn’t violating user privacy or security it shouldn’t be blocked, similarly to how the EFF's Privacy Badger extension behaves.

Transparency and control says that users should have the final say on how to control their experience and be able whitelist certain components of a site (or an entire site) as they see fit.

Finally, openness means content providers, such as site owners and advertising companies, should be allowed to interact with content blocking systems. That way if a particular behavior results in an advertiser being blacklisted there will be a mechanism in place to return to the good graces of a content blocker.

Mozilla’s new guidelines are really nothing new and you can find some or all of these principles at work with other organizations, services, and products. The Firefox add-on NoScript, for example, offers users detailed control over what does and does not get blocked on a particular site.