Yesterday
The New York Times reported on a new search-within-a-search option Google has made a standard feature of its site.
Now, if you search for certain high profile brands - Best Buy, let's say - you have the option of searching Best Buy Web only.

Very convenient for searchers, especially for sites with clumsy navigation or an enormous number of pages. The complications set in when you enter your Best Buy search term - in this case, "laptops" - and go to the new Google page. Here's what you get -

Notice the PPC advertising for
competitive sites. People searching for a laptop at Best Buy will view ads from HP, Dell, Tiger Direct, and several others.
What to make of this? Even with competitive ads, Google's new feature probably helps Best Buy. By organizing all of the retailer's many laptop options, Google saves the consumer time conducting internal searches on the Best Buy site for certain types of purchases or information. Sure, some customers will be lured away by the PPC ads, but most will likely stick with Best Buy, or at least review Best Buy's information, since they wouldn't have started there in the first place unless they intended to shop there.
On the other hand, Google may have leveled the playing field for brands with poor navigation and internal search capability. If my company has invested millions in developing a high quality site, I don't think I'd like that. Regardless of how it all pans out, this new feature highlights the enormous power of search engines to not only organize information, but influence outcomes.
Whatever the outcome for Best Buy, it's quite possible the new Google feature will be
a plus for PPC advertisers. The "Best Buy laptop" SERPs are of higher
quality to retail advertisers than SERPs for "laptops". Whether these
brand-specific pages yield a higher conversion rate for advertisers
remains to be seen. If they do, that's good news for Google. The
ultimate test will be whether consumers find the new Google search
option more convenient than simply searching the brand's actual site.