Duplication Detection

ohthere

Detecting duplication and notifying it when the user tries to add an article might be useful. This will save later efforts for manual comparison & merging. Similar feature exists in EndNote, although it works only on user's demand, not automatically. Identification of the duplication would be done with enough precision just by comparing the title and the year of publication.

adamsmith

you're right, but please use the search function before posting - this has been much talked about and seems to be pretty close to being released:
http://forums.zotero.org/discussion/42/duplicate-detection/