Well, it’s not so much ‘blocking’ as it is an option for Gmail’s iPhone app not to automatically display external images when people are reading emails. But that in turn will have an impact on some of the technologies used by marketers to track (for example) emails being opened. Not that this is the main reason Google has made the Gmail change: an option to ‘ask before displaying external images’ (which people have to turn on – by default the app will still always show images in emails) will also be useful for saving on mobile-data usage. It’s also a feature that Gmail Android users already have, so it’s merely extending that to iPhone.
Even so, it’s part of a wider trend that is reducing the effectiveness of some of the tools that marketers have relied on in recent years: see also Basecamp’s announcement last week that it is killing off its pixel-tracking features. “The tech industry has been so used to capturing whatever data it could for so long that it has almost forgotten to ask whether it should,” wrote its CTO David Heinemeier Hansson. “But that question is finally being asked. And the answer is obvious: This gluttonous collection of data must stop.” All this will require marketers to adapt, but in the bigger picture, it’s positive for internet users.