elasticsearch-entity-resolution
From the webpage:
This project is an interactive entity resolution plugin for Elasticsearch based on Duke. Basically, it uses Bayesian probabilities to compute probability. You can pretty much use it an interactive deduplication engine.
To understand basics, go to Duke project documentation.
A list of available comparators is available here.
Interesting pairing of Duke (entity resolution/record linkage software by Lars Marius Garshol) with ElasticSearch.
Strings and user search behavior can only take an indexing engine so far. This is a step in the right direction.
A step more likely be followed with an Apache License as opposed to its current LGPLv3.