(Previously discussed on GetSatisfaction here: http://j.mp/Uwdkcf )

This will enable us to sync our local media center (e.g. Plex Media Server) with the equivalent library section in our collections in Trakt without worrying that our other manually added items will be affected.

In other words we could have several sections in our collection. Firstly there are library sections for physical media that we manually add:

"DVDs" - Physical DVDs we own
"Blurays" - Physical Bluerays we own

Secondly, we could have the digital librarys that we own each be assigned a Media Center ID, such as:

"Home PlexMediaSever" - Our home NAS served by Plex Media Server
"Laptop PlexMediaServer" - Our portable Plex Media Server on our laptop

The media center ID will only be visible to each user but it will make it much easier to automatically clean our online Trakt.tv collection.

This way if we delete an item from our home Plex Media Server, on next sync it will be removed from our collection in Trakt online. However, if we move the movie/show to our other laptop PMS, on next sync the media player ID will be updated online to reflect this. In other whould one collection get hosed (i.e. disk failure it won't affect the other when we sync.

Also, syncing with a local machine needs to not only be able to add items to our collection on Trakt.tv, but also remove them - i.e. it needs to be able to do a true sync of the local data. XBMC (and other players) often misidentify items in our library and sync them to Trakt. When we fix the identification this needs to be synced up to Trakt. Without multiple library IDs. The machine might not know which library the shows/movies are stored on.