Now, $500 a share isn’t in the same stratospheric price range at which Google’s stock once traded–certainly it’s not the $707 and $713 it reached in 2007. But it’s a psychological milestone nonetheless, and that’s worth noting because Google’s shares have risen more than 50 percent over the past six months, and Wall Street seems to be growing increasingly more positive on the stock.

Sadly, the same cannot be said for Yahoo (YHOO), which hasn’t elicited the same sort of response. But then why should it? As Yahoo CEO Carol Bartz said earlier today, “Yahoo and Google are different companies. They are in different businesses….They aren’t us and we aren’t them.”

Clearly. Yahoo shares are trading at what, $16?

There are some customers which we chose not to serve. We don’t know how to make a $500 computer that’s not a piece of junk, and our DNA will not let us ship that. But we can continue to deliver greater and greater value to those customers that we choose to serve. And there’s a lot of them. We’ve seen great success by focusing on certain segments of the market and not trying to be everything to everybody. So I think you can expect us to stick with that winning strategy and continue to try to add more and more value to those products in those customer bases we choose to serve.”

– Apple CEO Steve Jobs, Oct. 2008

Perhaps Macworld Expo 2009 will have its “one more thing” after all.

In a note to clients this morning, Ezra Gottheil of Technology Business Research speculates that Apple (AAPL) will indeed launch a new product category at Macworld in early January. A netbook designed to leverage Apple’s design prowess and its online delivery system as well. “[The device] will provide Web access, email, media playing, and essential applications at a single low price,” Gottheil writes. “Computer beginners will be able to start using it quickly and easily. Users will have fewer questions, problems, conflicts and security breaches, as the device will be less intimidating than both PCs and Macs. As with the iPhone, iTunes and the App Store will offer an array of content, applications and games. As with the iPhone, the software can be rebuilt from the App Store. With an optional online backup service, the entire device can be restored…. Because all applications are delivered through the iTunes App Store, Apple will maintain sustained relationships with users, making it easier to upsell and cross-sell to existing customers. TBR believes Apple will make online services like MobileMe increasingly attractive to all customers, but purchasers of the new Apple device may find its simplicity especially appealing.”

Now, I know Gottheil’s the guy who said “Apple doesn’t need Jobs anymore”–blasphemy! But the scenario he lays out above makes quite a bit of sense, doesn’t it?

If such a device is indeed uncrated at Macworld, Gottheil expects it will arrive at market around midyear at prices beginning at $599–$99 more than the $500 computer Apple CEO Steve Jobs claims the company doesn’t know how to make….