What Hampers the Mobile User Experience?
Popup’s that cover the main content area and not allow the user to view it.
ALSO SEE: Optimizing Your Site Content for Mobile Audience
Displaying interstitials that needs to be closed in order to access the main content area.
However, not all interstitials are bad. Some that inform the user about cookie usage or a popup for age verification or a popup that does not covers the entire mobile screen are all valid usage of popups that won’t be affected by the coming January update.
The main point that matters is, users should reach your main content from search and there should be no mandatory obstructions to it.
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