I have no idea what ElasticSearch is. To be honest, our search capabilties s*cks and that is Google search. It does not load last day or two so. Furthermore, search in own post and comment history is not possible, I think Google does not look into comments, but did not play around with to much. That basically means, a lot extra time for posters to use something already written in the past. So inconvenient. Also even Chrome is too slow in get the next batch of 20 posts, that is why in my view most posts at position 80 or 100 in one of the general channels get lost for everybody. Hence, the gamers in the community will seek optimal time to post to get most rewards etc. This really needs to change to get retention of a lot more users.

EDIT: comparison between ElasticSearch and Cassandra, didn't read it yet myself: http://stackoverflow.com/questions/27054954/elasticsearch-vs-cassandra-vs-elasticsearch-with-cassandra