It’s an interesting distinction for Portland. An online dating website has released results of a poll that ranks Portland as the nation's "Most Promiscuous City."   Okcupid.com has listed the ten cities most interested in casual sex, and Portland heads that list. According to the Huffington Post, the dating website based its rankings on the percentage of users in each city who list "casual sex" among what they seek in a relationship.  Seattle ranks second on the list.