During previous recent market downturns Google (NASDAQ: GOOG) has held up well. This past week the NASDAQ stocks have been retracing their steps, giving back a sizable portion of their recent gains. Google, though, has been giving back more than most over the past two days, slipping about 10% off its high.

There could be any number of reasons. Dubious earnings reports from other tech companies might be the culprit. Or it could be the news that AOL is buying Quigo, giving the appearance of some vulnerability. To me, that does not seem like it would be a major factor either. There is plenty of dour economic news at the moment, but that hits everyone. Google established a recent new all-time high of $747.24, but is trading around $671 now and has traded down as low as $663. (UPDATE: GOOG closed at $663.97 on Friday.)

Every indication is that Google is not that expensive compared to other rivals. Until I hear some negative news that is specific to Google, I think a large portion of this drop can simply be attributed to profit taking. There is plenty of juggling going on in the fund market this time of year. Have you been re-balancing your portfolio? Have you been taking profits? Is there some other reason for the sell-off? Where might Google land? Is this a buying opportunity, or if not, at what price do the Google bulls stop the slide? Some say short the stock, maybe, and maybe you get creamed -- that I would not do unless you have really deep pockets.

To find potential opportunities and verify my track record, read Chasing Value or Serious Money.

Sheldon Liber is the CEO of a small private investment company and the principal for design and research at an architecture & planning firm.

An interesting little factoid, or opinionoid, came about today, concerning Quigo, which was just purchased by AOL.

On today's "Stop Trading" segment on CNBC at 2:45 PM, Jim Cramer was discussing the hit in tech stocks and the markets. Google (NASDAQ:GOOG) was addressed since it has suffered a 5% drop (nearly $40 a share) and is back under $700 today.

Interestingly, Cramer tied some of Google's weakness to Time Warner Inc.'s (NYSE:TWX) action of having the AOL unit acquire Quigo for its contextual advertising platform. Cramer said he's evaluated Quigo and said it is actually better than Google's ad platform.

I have heard that the system is a great one, but I haven't heard an independent voice that say this as of yet. (Full disclosure: BloggingStocks is an AOL unit and Cramer and I both write for BloggingStocks, so neither of us are completely removed from AOL).

Of course, on a day like today, Cramer's Quigo plug isn't generating much help for TWX shares, which are down 2% at $17.50 as of 3:15 pm

A separate point from the CNBC segment today: While Cramer noted the earnings report from Cisco Systems inc. (NASDAQ:CSCO) was a negative indicator for technology, he said he'd actually buy Cisco here since the conference call wasn't all that bad.

Reports have been circulating throughout the Israeli press, that AOL (NYSE:TWX) is set to buy Israeli start-up Quigo, for $300 million. Quigo's AdSonar competes with Google's AdSense (NASDAQ:GOOG), placing links on search results, while its FeedPoint product serves up ads on search results or Internet sites, relating the ads to the user's interests. This technology is revolutionizing online advertising as advertisers can really start targeting appropriate consumers, and maximize their advertising budgets.

Many Israeli analysts believe that this deal may open up the door for further M&A with Israeli companies. In 2007 over $20 billion was invested in Israel, including HP's(NYSE:HPQ) $4.4 billion purchase of Mercury Software. So far 2008 has been slower, but this deal may just be what the doctor ordered. Many Israeli companies have been mentioned recently as potential takeover targets. Companies like alternative energy innovator Ormat(NYSE:ORA), supply-chain operator Retalix (NASDAQ:RTLX) are just a few worth mentioning.

Disclosure: Writer holds a position in ORA and RTLX. He has no other position in any stock mentioned as of 11/4/07.

Aaron Katsman is the lead Portfolio Manager and Managing Director of America Israel Investment Associates, LLC. and Senior Editor of IsraelNewsletter.com.

It seems like Google (NASDAQ: GOOG) is the only Internet ad company that matters. But, hey, not long ago this was a mere startup, too.

And, yes, there are a variety of competitors looking to get a piece of Google's franchise. Take Quigo. The company has a system, called AdSonar, which allows for auction-based, pay-per-click advertising. The company is gaining traction, getting deals with companies like ESPN.com, CAREER BUILDER, Cox Newspapers and McClatchy Company (NYSE: MNI) and others. I had a chance to interview Quigo's Chief Revenue Officer (CRO), Henry Vogel.

Q: How are you differentiated in the marketplace?

A: First and foremost, our transparent approach makes publishers more money. For example, advertisers in the Quigo network can determine on which sites and in many cases, on which specific pages within those sites, their ads will be placed. And, they can set different bids for each placement (site, page, contextual topic and so on). As such, our publishers -- especially the tier one, branded sites with high-quality traffic -- will make more money because advertisers will bid up the prices to be on their premium sites and connect with their high value traffic. We call this the "bid-to-brand" effect. In contrast, when publishers are bundled into a blind network where advertisers can only bid on a keyword or group of categories and don't know on which sites or pages their ads will be placed, they simply bid less because they have less certainty and no ability to optimize their returns.

Second, if you dive into some of the technical components of our system, there are several other factors that help drive superior results for consumers and publishers. These factors include such things as our relevancy and yield optimization algorithms, which not only help predict which advertisers will have higher click volume, but also optimize the aesthetics of our ads within a given style guide. We're able to alter over 36 different aesthetic variables and isolate the font size, color, backgrounds, borders and the like in real time in order to serve ads that will deliver the highest returns.

Q: Your system also allows a publisher to own their advertiser relationships, right?