"I have met many great people who I otherwise would not have met."

Should who or whom be used?

Whom is the correct word. It's the object of the verb, "would have met."

Use whom, which is correct.

To determine whether to use "who" or "whom" in this sentence, you need to identify whether the pronoun is the subject or the object of the verb "met."

In this case, the pronoun in question is the relative pronoun that introduces the subordinate clause "who(m) I otherwise would not have met."

To decide which pronoun to use, follow these steps:
1. Identify the verb phrase: "would not have met."
2. Determine the doer of the action (subject): "I."
3. Identify the person who is being met by the subject: "many great people."

Now, we need to determine if the relative pronoun refers to the subject ("I") or the person being met ("many great people").

If the relative pronoun is the subject of the verb inside the subordinate clause, we use "who." If it's the object, we use "whom."

In this case, the pronoun "who(m)" is the object of the verb "have met" in the subordinate clause. Since it refers to the people being met, we should use "whom."

Therefore, the correct phrasing would be:
"I have met many great people whom I otherwise would not have met."

Keep in mind that in casual conversation or informal writing, "who" is occasionally used in place of "whom," especially when the pronoun is the object of a preposition. However, in formal writing or when aiming for grammatical precision, "whom" is more appropriate here.