https://www.juicer.io/blog/what-is-a-search-aggregator-and-why-should-i-use-it
What Is the Difference Between a Search Aggregator and a Metasearch
Engine?
Sometimes the terms search engine aggregator and metasearch engine are
used interchangeably, which is understandable because they are similar
in many ways. In fact, a search aggregator is actually a specific type
of metasearch engine, which gathers results from multiple search engines
simultaneously usually using RSS search results.
According to Wikipedia
<
https://en.wikipedia.org/wiki/Search_aggregator>, search aggregators
are an increasingly popular way to take advantage of the power of
multiple search engines with a flexibility not seen in traditional
metasearch engines. To the end-user, a search aggregator may appear to
be just a customizable search engine and the use of RSS may be
completely hidden. However, the presence of RSS is directly responsible
for the existence of search aggregators and a critical component in the
behind-the-scenes technology.
What Search Aggregators and Metasearch Engines Are Out There?
While many search aggregators and metasearch engines have either become
bankrupt under the crushing weight of Google or were brought up by
Google (or one of its many competitors), there are still plenty of
uniquely wonderful search aggregators and metasearch engines out there.
23 Metasearch Engines & Search Engine Aggregators and When to Use Them
As we’ve mentioned before, a metasearch engine is a pre-programmed
search engine aggregator with a specific function in mind for the search
results from multiple search engines. Because these search aggregators
are designed with a particular benefit in mind, they are each beneficial
for different situations.