Outside of government agencies (e.g. .gov, .gov.uk, .gouv.fr and more), other TLD are not as informative as you might think. Anyone can register .edu or .org sites, whether or not they are educational or non-profit institutions. Similarly, country TLD are not always limited to people operating in that country.
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Before using the information found, you should assess its quality and relevance. The following methods can be applied to make sure every source you plan on using in your research assignment is reliable:
Be aware that Google use algorithms (PageRank) to filter, or tailor, the search results, based on previous searches you have done – the sites you have viewed, what you clicked on and other data that can be gathered from your browser. So the exact same search, using exactly the same search words, can return different results for different individuals.
Get further:
Pariser, Eli. "Beware online filter bubbles." Filmed February 2011 in Stockholm, Sweden. TED video, 8:47.
https://www.ted.com/talks/eli_pariser_beware_online_filter_bubbles