Over two years ago I had an automobile to sell. I opted for a combination of the conventional--print newspaper--and the relatively new--the Internet. My local newsaper provided the link for both outlets, a convenience that failed.

The newspaper interface offered interaction with a live person, who cheerfully took my ad and credit card number. I had no interaction whatsoever with Cars.com, the Internet sales channel. My newspaper ad terminated on schedule, but the Cars.com ad persists to this day. Worse yet after asking Cars.com via email to discontinue the ad, I received notification that I the car seller had no authority to terminate the ad, only the newspaper. Repeated efforts to contact my local paper have failed. So if you are in the market for an inexpensive 1999 Camry in State College on Cars.com disregard my ad.

The lesson: regardless of the wonderful reach provided via the Internet, a human interface probably remains essential. Should that interface fail, be prepared for more hassle than you might have expected. In my case I have to disappoint callers and emailers that they missed the chance to buy a cheap Camry by about 30 months!