Elastic search

Elastic search is an open-source search software built on top of Lucene, like another popular competitor Apache Solr. I first came aware of it in a search for an enterprise search solution, and replace for google search appliance. Being open source, it wasn't as refined as many commercial products, however it was slated as being the next great thing, in search and a big data. I believe it is search technology of choice for all Blockchain based search solutions including Etherscan.

It doesn't have a lot of visual tools with it, so you have to plug-in third-party tools or extensions such as Kibana for visual representation of the data.

I believe it is one of the core technologies used in Elastic Intranet.