Trends come and go and, if you wait long enough, they circle back around. It’s been true for bell-bottom pants, hairstyles and wool pea coats and it’s now true for the U.S. mail! I had to chuckle at a recent reTweet I received, highlighting “Letters in the Mail” service by The Rumpus. An introductory paragraph explains: “Almost every week you’ll receive a letter, in the mail. … Think of it as the letters you used to get from your creative friends, before this whole internet/email thing.” To clarify, one letter is written and signed and then copied and sent to all who subscribe. And, some of the letter writers will…