There’s been a whole wealth of controversy over iOS9 content blocking (sometimes called ad blocking), a new feature in the latest iPhone/iPad operating system, and I was unclear where I stood on the debate. That is, until I ran some tests.

Many Web site owners make an income from showing adverts on their sites (some make all their income this way). But in the past couple of years, the size, quality and sheer invasive qualities of ads has grown to be annoying. I won’t pick on any particular advertisers, but we’ve all seen them – huge ads that have a tiny close button on them (somewhere you don’t see initially is the usual form). Or lots of ‘promoted stories’, or ‘clickbait’ as it’s often known (gossipy/sensational stories that have you click into them to be presented with more ads than story).

What you need to remember is that the ads don’t come from the actual Web site. Each site will ‘sell’ space to one of a limited number of web ad agencies, and have limited or no control over the ads served through their site. So when you go to that site, it will then send your browser off to many other domains to pick up content to display on the page you see. A good content blocker knows which of these other domains are known advertising networks, behaviour analysis and tracking sites…..and prevents your browser from referencing them. The advertising networks pay the actual site owner a small fee for every advert that gets loaded into your browser.

The arguments against content blockers is that it removes this source of income from site owners. There’s also the ethical argument that some content blockers may begin to sell space on their apps whitelist to ad creators (that may happen, but I’ll just change to a different blocker that doesn’t do it). Already, many of the content blockers available allow you to add a whitelisted site, meaning that all ads on that site will show. So if you want to protect the income of your favourite blogger, you can do so easily.

So that’s the theory, and it leaves me a little cold other than the fact that some ads are annoying. I wanted to test what a difference having a content blocker loaded made to my browsing experience. Using a relatively short list of sites that I use on a daily basis, I cleared my Safari data, reset my usage monitors and loaded the sites in order, first with content blocking turned off, then with it turned on (after clearing any caches again of course).

I chose the Content Blocking app Purify (normally £2.99, but currently on offer at £1.49), but there’s plenty of others to choose from. Crystal is another one that gets recommended quite highly.

The same page with & without blocking turned on

From a purely visual point of view, the difference in results was night and day. With content filtering, there were no banner ads at the top of every page. Background ads were gone, as well as promoted stories and you know those annoying adverts showing you places to buy the very same product you bought yesterday – gone too. With the sites I chose, there was nothing missing that was important to me (and if there had been, I can reload the page with filtering turned off by holding the refresh icon down and selecting ‘Reload Without Content Blocking’).

Load speed was much, much quicker (difficult to measure, but perceivably faster for me). The browser didn’t have to wait while it was sending and receiving information relating to my activity between it and multiple third party sites. It served the information I asked for, nothing else.

Last, but not least, I checked the amount of data used in viewing 4 sites with filtering turned off and on. What I found was pretty unbelievable. The data use was almost tripled with filtering turned off (in this small sample 32.1MB vs 12.6MB) which could make a huge difference to someone with a small data allowance on their iPhone tariff.

In summary…..should you use iOS9 Content Blocking? Without a shadow of doubt, yes. It’ll make your browsing experience quicker, cleaner and more efficient. What’s not to like about that?