This is a delicate art. Suggest-selling can enrich the customer's experience. My mother ran a bookstore and I didn't like doing sales and suggesting additional books. I was never pressed to, but I noticed that other employees could suggest an appropriate related book without pushing the sale.
It wasn't often that the customer would take it, but because it was appropriately related, they wouldn't lose out on the experience, and if they did like it, it was higly positive and a win-win situation. A skilled salesperson is interesting to observe.
Or maybe, in the style of "salesmen who can't say no":
"Is it a thriller?"
"Is a romance?"
"Is it an accurate historical account?"
"Is it science fiction?"
"Is it easy to read?"
"Who is the author?"
"Who would you like the author to be?"
[NB I really have been the sales engineer in meetings like that and I found them to be awful - no amount of kicking under the table or subtle hand signals would stop some people]
Oversell in retail means in my thoughts: talking somebody into buying stuff he really don't need. Like the 6th shoe cleaning spray for your new leather shoes.
The adwords model came from goto.com (then overture.com) which was entirely ads that you searched. Like searchable classifieds I guess.
Remarkable to see companies that have lasted more than 1,000 years! And sad to see that Kongo Gumi - a Japanese construction compnay - shut down in 2006, after being founded in 578 CE.
And founding a brewery in the 1400ies was really a good idea.