The Pages I'm Following is a Wikia feature that adds a list of pages a user is following to their user page.

How to disable itEdit

Hide the list on all user pages Edit

Add the following code to your wiki's Common.css

// Hide the list of followed pages on user page
#profile-sidebar, #userPageFollowedHead { display: none !important; }

Disable the list for you on all Wikia Edit

You can make that list private for you on all wikis by setting an option in your Special:Preferences: Just enble the option Make my followed pages list private under Followed pages section.