Learn English – the appropriate verb and preposition to say “play the lottery”

We have preferences for things more often than preferences of them, but of isn't incorrect here, nor the only alternative: as to, regarding, in regards to, and the like would also work. Rather than asking for a preference for, why not ask what the addressee prefers?

I would like to meet with you. Is there a time or place you prefer?

I would like to meet with you. Do you prefer a particular time or place?

You send parcels and letters to people. You send emails to mailing lists.

I was informed about this position by the ad sent by John Doe to the Foobar mailing list.

You would only use in if the mailing list is actually a list of people containing John Doe, and the sending of the emails to it is irrelevant. Using in here is the equivalent of:

I was informed about this position by the ad sent by John Doe, who is in the Foobar mailing list.

I suspect you mean the first, not the second, in that you saw the ad because you were following the list.

Edit (following your edit):

I was informed about the position via the Foobar mailing list.

This is perfectly good. You could also say:

I was informed about the position via John Doe's ad on the Foobar mailing list.