I just noticed that we're involved in the Project Reduplication of Deduplication initiative, along with only 10 other sites!
Open to close voters only, you can now help Stack Exchange and the University of Melbourne work on automatically detecting duplicates.
More information is available in this uber-meta post:
Project Reduplication of Deduplication Has Begun!
As of right now, there are currently 1079 question pairs to be annotated for the WordPress site.
You can log in using your StackExchange account here to take part:
http://hum.csse.unimelb.edu.au/se-annotate/
(note: even though the uber-meta post says it's open to close voters only, I seem to be able to take part even though I'm less than 3k rep... so maybe give it a go anyway even if you don't have close vote privileges yet!)