prepositions - I don't see the point of/in doing that

Please tell me when should I say Of and when should I say In.

For example consider the sentence below.

I don't see the point of/in doing that.

Answer

In my native dialect, mid-Atlantic American English, here is how it works.

If you want to talk about "the point" and you're talking about an action, use "of" plus a verb.

If you are talking a noun rather than a verb, use "of". Using "in" or no preposition is not correct.

However: if you are saying "any point" or "no point", you can say "in" but not "of," whether you're talking about a noun or a verb, and in some cases you can drop the preposition entirely.

So the following are correct:

I don't see the point of Stack Exchange.

I don't see any point in Stack Exchange.

I see no point in Stack Exchange.

I don't see the point of posting on Stack Exchange.

I don't see any point in posting on Stack Exchange.

I see no point in posting on Stack Exchange.

There's no point posting on Stack Exchange.

There isn't any point posting on Stack Exchange.