This is the 8221st most frequent Russian word.
майклу
"Майклу" is the dative case of "Майкл," the Russian transliteration of the name "Michael," meaning "to Michael" or "for Michael."
In this sentence, "Майклу" is a dative case form of "Майкл". It is used because the verb "нравиться" requires the person experiencing the liking to be in the dative case.
Майклу нравится путешествовать.
Michael likes traveling.
Here, "Майклу" is in the dative case, which is used as Michael is the indirect object, receiving the book.
Я дал книгу Майклу.
I gave a book to Michael.
Again, "Майклу" is in the dative case as the verb "звонить" (to call) requires the person being called to be in the dative case.