I've gotten fewer and fewer of those letters or postcards. A lot of them are going to direct email marketing (spam), though I've questioned what they do if there is no email on file...
On an unrelated note, I received no bill from a doctor for a visit, and after nearly 6 months I gave them a call to see if there was a balance, or if my insurance had paid. No, my insurance hadn't paid, and I had been sent to collections because I never paid the bill. I never got a bill in the mail. The response was, "we emailed you the bill". Really? What email address did you send it to? "Umm... There's no email on file for you"... There was no apology, and the collection service likewise had emailed the collection notices to "null". I had to jump through a few hoops to get this taken off my credit report, and I started monitoring that more closely.
