TVmaze currently has 6 different access levels: Admin, Head Contributor, Curating Contributor, Trusted Contributor, Supporting Contributor and Contributor.
Contributor: this is the starter level for every new user. A contributor can change most of the data on the site unless that value has been edited too frequently; can create everything besides shows, networks and web channels (so you can create people, episodes, cast, guest cast, etc); but can't delete anything at all.
Most attributes can only be changed by a regular Contributor 3 times before they're locked for editing to prevent edit wars. Additionally, a Contributor can't create any items when an item with the same values already existed in the past.
Supporting Contributor: can add shows, have access to dataentry tools and edit logs.
Trusted Contributor: can change all of the data on the site, also properties protected from editing by Contributors like show names and actor names. They can also create all data on the site; including shows, networks and web channels. They can delete most entries on the site; but can't delete important items like aired episodes, shows, networks and web channels. In addition, they can use various bulk editing and importing tools.
For TC's we allow the double amount of edits to an attribute before it's locked, which means 6 changes for the most attributes. They can also re-create an item which already existed previously one single time.
After that comes the Curating Contributor. The Curators are responsible for safeguarding the correctness of our data, especially for the complicated scenarios. They can do everything the Trusted Contributor can, but they are also able to edit attributes that are locked to regular users or Trusted Contributors after repeated back-and-forth editing. They can also recreate previously deleted items without any limits. Finally, they can also delete aired episodes & seasons, write show wiki's, write private messages to other users, use the merge tools and edit external (imdb, thetvdb, etc) ID's.
On top is the Head Contributor with unlimited editing access to all of the site's data. They can also manage contributors' editing thresholds, which allows people to continue editing after their edits have been automatically flagged for review.
Finally the Admins have full power over any aspect of the site.
Currently every registered user with a confirmed email address starts off with Contributor access, which means anyone can sign up for an account and start contributing data to TVmaze if something's missing or incorrect. We hope to keep the barrier to editing as low as possible, but of course the site administrators are monitoring all changes and depending on the quality of these contributions we might have to introduce some extra safeguards later on.