  Search engines play an essential role in our daily lives. Nonetheless, they
are also very crucial in enterprise domain to access documents from various
information sources. Since traditional search systems index the documents
mainly by looking at the frequency of the occurring words in these documents,
they are barely able to support natural language search, but rather keyword
search. It seems that keyword based search will not be sufficient for
enterprise data which is growing extremely fast. Thus, enterprise search
becomes increasingly critical in corporate domain. In this report, we present
an overview of the state-of-the-art technologies in literature for three main
purposes: i) to increase the retrieval performance of a search engine, ii) to
deploy a search platform to a cloud environment, and iii) to select the best
terms in expanding queries for achieving even a higher retrieval performance as
well as to provide good query suggestions to its users for a better user
experience.
