Amazon.com (NASDAQ:AMZN) has upped the ante in its bid to make up for lost time against its entrenched search rivals -- and it's using its own strength in e-commerce to do it. They've been keeping it pretty secret though, at least so far -- Motley Fool Stock Advisor pick Amazon is offering an additional, small discount to its already lowered prices to shoppers who click over from its newly launched search engine, A9.com.

I have to give props to someone over at Search Engine News Journal, as well as to one of the alert members of our own Amazon.com discussion board, who both pointed out the A9.com perk, where cleverness abounds, if not deep discounts.

Let's say that like me, you were sad to hear that Johnny Ramone had passed away, leaving only one surviving Ramone. So you did a search on Johnny Ramone, clicked on one of the many books by or about the Ramones, which takes you, of course, to Amazon. Under "Ready to Buy?" you see "A9 Instant Reward Active." Click on that, and you see a description of the 1.57% discount that is applied to any purchases powered by an A9.com search. ("Sharing the pi" -- pretty clever.)

There's more than a little Googling (NASDAQ:GOOG) going on here, though, I think, even beyond the mathematical jokes. The description of the discount includes this paragraph: "We don't advertise this additional discount that we give in exchange for using A9.com, so if you want your friends to know about it, please tell them. It is probably the only way they'll find out. All they have to do is use A9.com as their regular search engine. They should make sure they are signed in to A9.com (it should be recognizing them by name) so that we can be certain they get credit for their visit."

That smacks of the insider-type viral marketing that Google used in its interesting, invitation-only Gmail launch, and maybe even a nod to Friendster-like social networking schtick. It explains that it funds the reward through sponsored links... again, smacking of Google's advertising-funded gigabyte of email storage.

On Wednesday, I admitted that some people might get a little creeped out by A9's heavy e-commerce theme threaded into search endeavors. (However, Amazon has said that users may choose a version of A9.com that turns off their identifying cookies, likely a smart move for the squeamish.)

However, when I pooh-poohed all the privacy howling over Gmail last spring, I felt that in certain cases, consumers might not mind a little e-trail, if the benefits are compelling enough. Further, it's arguable that Amazon's not doing anything terribly different than loyalty cards issued through grocery stores, pharmacies, and so forth -- after all, they generally track what kind of peanut butter or hand lotion you've bought and offer the occasional extra savings for your "loyalty," if that's what you call it.

A9.com's added discount is a clever marketing gimmick, meant to give an extra leg up to its search engine, which was late getting out of the gate. However, as the connections between search and e-commerce become more deeply intermingled, at what point search users decide search has become too smart will be interesting indeed.

Is Amazon going too far? Or will it rapidly swipe searchers from Google and Yahoo! (NASDAQ:YHOO)? Talk about the issues on the Amazon.com discussion board.

Alyce Lomax does not own shares of any of the companies mentioned, but she would like to thank everyone who submitted guesses as to what A9.com stands for -- the consensus is, it stands for "algorithm," which has nine letters starting with "A."