Reader mode is a Safari feature, which strips out most of the formatting from a webpage, removing adverts, navigation links and comments

Twitter is testing a new feature on its iOS app which turns on Apple’s “Reader” mode by default on every link opened in its in-app browser.

First introduced in 2010, and ported to iOS in 2011, Reader mode is a oft-forgotten feature in Safari that strips out most of the formatting from a webpage, removing adverts, navigation links, comments, and almost everything else except for the main content of a text-based article.

In the new test from Twitter, rolled out for a small number of users – including one Guardian reporter – the company has enabled Reader mode by default on every single link clicked.

While the new feature can be a boon for those navigating badly designed web-pages, it also manages to mangle the presentation of almost as many sites. While the feature works well for traditional news articles, anything that isn’t a chunk of text-heavy content in the middle of a page falls apart.

The change will also be worrying for many media organisations: unlike similar light-weight webpage options, such as Facebook Instant Articles and Google’s Amp project, there’s no option to customise the appearance of the Reader version of the page, nor any ability to monetise the views.

Reader still requires the original version of the page to be loaded before it can display, however, which may mean advertising figures are still counted – at least until advertisers realise that some proportion of readers aren’t viewing the adverts.

A Twitter spokesperson confirmed that the change is “just a test for some”, but it comes in the middle of a number of other large changes being tested by the company. Most notably, Twitter is also testing a new system for replies on the site, which has been received with extraordinarily negative response from those in the test. “I understand completely that this is just a test of something Twitter might do,” wrote TechCrunch’s Matthew Panzarino, “I am just encouraging them very strenuously not to.”

The new replies functionality, among other things, makes it much harder to remove people from threads, hides who else is in a thread, and removes from notification tabs any mention of whether or not there is a broader conversation at all.