4. A web search engine is a software system that is
designed to search for information on the World
Wide Web. The search results are generally
presented in a line of results often referred to
as search engine results pages (SERPs). The
information may be a mix of web pages, images,
and other types of files. Some search engines
also mine data available in databases or open
directories. Unlike web directories, which are
maintained only by human editors, search
engines also maintain real-time information by
running an algorithm on a web crawler.

5. Google Search, commonly referred
to as Google Web Search or
just Google, is a web search
engine owned by Google Inc. It is
the most-used search engine on
theWorld Wide Web, handling
more than three billion searches
each day. As of February 2015 it is
the most used search engine in the
US with 64.5% market share.

6. Bing (known previously as Live
Search, Windows Live Search, and MSN
Search) is a web search engine (advertised
as a "decision engine") from Microsoft.
Bing was unveiled by Microsoft CEO Steve
Ballmer on May 28, 2009, at the All Things
Digital conference in San Diego, California,
for release on June 1, 2009. Notable
changes include the listing of search
suggestions while queries are entered and
a list of related searches (called "Explore
pane") based on[5] semantic
technology fromPowerset, which Microsoft
purchased in 2008.

7. Yahoo Search is a web search
engine owned by Yahoo. As of
February 2015 it is the third largest
search engine in the US by the query
volume at 12.8%, after its
competitors Google at 64.5%
and Bing at 19.8%.

8. Ask.com (originally known as Ask
Jeeves) is a question answering-
focused web search engine founded in
1995 by Garrett Gruener and David
Warthen in Berkeley,California. The
original software was implemented
by Gary Chevsky from his own design.
Warthen, Chevsky, Justin Grant, and
others built the early AskJeeves.com
website around that core engine. In late
2010, facing insurmountable competition
from Google, the company outsourced its
web search technology and returned to
its roots as a question and answer
site.[2] Douglas Leeds was elevated from
president to CEO in 2010.

9. DuckDuckGo (DDG) is an
Internet search engine that emphasizes
protecting searchers' privacy and
avoiding the filter bubble of
personalized search
results.[1]DuckDuckGo distinguishes
itself from other search engines by not
profiling its users and by deliberately
showing all users the same search
results for a given search
term.[4] DuckDuckGo emphasizes
getting information from the best
sources rather than the most sources,
generating its search results from
key crowdsourced sites such as
Wikipedia and from partnerships with
other search engines
like Yandex, Yahoo!, Bing,
and Yummly