Ngram

Ngram

 

1. Ngram lets you look up certain words and see how much they have been used. You can search up anything from names to toys.
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3.  URL link: https://books.google.com/ngrams/graph?content=Marvel+superheroes%2C+DC+superheroes&year_start=1968&year_end=2008&corpus=15&smoothing=3&share=&direct_url=t1%3B%2CMarvel%20superheroes%3B%2Cc0%3B.t1%3B%2CDC%20superheroes%3B%2Cc0
4. You could use this best in English. To look up words that you don't know. Also to look up how much certain words are used.
5. I did not face any challenges. It is very easy to work. You don't even need a tutorial.