which is/who are

The second sentence is incorrect on two counts.
1) "Internet provider" is a singular subject and should, therefore, take a singular verb as a predicate, a condition which "who are" does not meet.
2) "Internet provider" implies an inanimate entity. The pronoun "who" is generally used to refer to a person.

Yes, both are correct. The point of view, however, can differ from one group of English speakers to another. Speakers of the American language tend to see a corporation as an entity, a "thing," and not a person, so an American would probably use sentence 1.

Sentence 2 is not necessarily incorrect, but sounds awkward, to my ear at least. Native English-speakers who speak British English frequently refer to a corporation of a government agency which is comprised of a group of people as though one were referring to a group of people, so sentence 2 would be correct from that point of view.

A simpler example might make this more clear to you. An American would say: "The staff is not happy with the changes." That treats the noun "staff" as a "thing," an impersonal entity, and uses the singular verb form. A speaker of British English, however, would likely say: "The staff are not happy with the changes." That person assumes that "staff" refers to a group of people, and therefore uses the plural verb form.

So, basically either sentence can be considered correct, and one would assume a speaker of the American language had written the first sentence, and a non-American English-speaker had written the second sentence.

That is the logic of the American language. It is not necessarily the logic applied by all native speakers of the English language.

I have to disagree with you, Set. Even conceding that an inanimate entity e.g. "internet provider" may, under some circumstances, be referred to with a pronoun e.g. "who," the singular "are" is still wrong. Subject/verb agreement is a basic rule of proper English.

Disagree to your heart's content, MA, but it won't change the logic which many other English speakers apply. In the example which i provided about "staff," many English speakers consider that to be a term for a collection of people, so they use "who," and they consider that subject-verb agreement requires them to use the third person plural--"the staff are."

Tell ya what . . . you think your way, and i'll think mine.

I believe it was Churchill who said "we are two nations separated by a common language".

Meanwhile, we've just confused the hell out of poor Yoong Liat!!

When I was younger, I used to go to the movies and before the movie started, it would state the company producing it.

Sometimes I see 'ABC Company presents" and sometimes 'XYZ Company present'. I was initially confused. However, when I read English usage books, some of them state that both are correct. If regarded as an entity, use 'presents' and, on the other hand, if considered as staff in the company use 'present'. But recently, when I told my friend about this, he said that only 'presents' is correct.

I must add that the books I read are on BrE usage. I've also read that Americans prefer to use the singular for collective nouns, such as company.

I'm posting the query so as to prove to my friend that he is wrong. Unfortunately, I've given my English usage books away or else I could have proved to him by using the books.

There are many examples of this--Americans say "the government is" while the English commonly say "the government are." I think your point is well established, even if those of us who have responded here do not agree about it.

Thanks.