User accounts on a wiki are assigned to different software groups, each with their own set of privileges (such as being able to edit generally, or block accounts). See the user groups rights page for a full list of user groups. To see what groups you are a member of, click 'My preferences' while logged-in to this wiki.
By default, new users are marked as 'Users' and 'Autoconfirmed users'. 'Users' may edit most pages; 'autoconfirmed' allows few or no extra privileges on this wiki but is imposed by default.
Note that on Citizendium, 'Editor' is a status awarded to contributors who are subject experts. There is a user group called 'Editors', but it has no special privileges not provided by other groups. By default, the wiki software makes any user who can edit it a 'wikieditor'. This name was changed on Citizendium to 'editor' early on in the project, then withdrawn for new accounts. This is why some users are marked as 'editor' - it has nothing to do with whether they are subject experts or not.