List of enterprise search vendors

Free and open source enterprise search software

30 Digits - Implementation, consulting, support, and value-add components for Lucene and Solr
Apache Software Foundation - The foundation is the entity behind the Lucene family of products
LucidWorks (former Lucid Imagination) - Commercial support, training and services for Lucene and Solr
Customermatrix (acquired Polyspot, CRM development and products for Lucene)
Searchblox - Commercial product for Lucene and ElasticSearch
Sematext - Consulting, development and products for Lucene, Solr, Nutch, and Hadoop
Flax - Architecture, development and support for Lucene, Solr and Xapian

AskMeNow
Attivio
Concept Searching Limited
Content Analyst Company LLC
Coveo
Dassault SystÃ¨mes (acquired Exalead)
Denodo
Dieselpoint, Inc.
dtSearch Corp.
EMC Corp.
Exorbyte GmbH
Expert System S.p.A.
Exterro, Inc.
Fabasoft
Funnelback
Google Search Appliance
HP (acquired Autonomy Corporation which in turn acquired Verity K2 and Ultraseek)
IBM (acquired Vivisimo, rebranded "Watson")
Inbenta
inter:gator Enterprise Search
ISYS Search Software
Lookeen
MarkLogic
Microsoft (includes Microsoft Search Server, Fast Search & Transfer)
Mindbreeze
Neofonie (includes WeFind)
Omniture (acquired by Adobe Systems)
Open Text Corporation
Oracle Corporation (includes Secure Enterprise Search and Endeca Technologies Inc.)
Q-go
Q-Sensei
Recommind
SAP (includes SAP NetWeaver Enterprise Search, Search Services in SAP NetWeaver AS ABAP, and Search and Classification TREX)
Silent Eight
Sinequa
SLI_Systems
Sophia Search Limited
Swiftype
TeraText
Thunderstone Software
X1 Technologies, Inc.
ZyLAB Technologies
ZL Technologies