This could mean a lot of things, but I'll take a stab at something that comes to mind because of issues you've posted about here...
You've posted a lot of times in previous threads about Google ranking your pages as information pages, whereas you wanted visitors to buy from you...
What To Do? Monetize Versus SEO
http://www.webmasterworld.com/google/4319384.htm [webmasterworld.com]
When Should You Remove Information Section From Ecommerce Site?
http://www.webmasterworld.com/google/4419155.htm [webmasterworld.com]
etc
Most recently, in this thread...
Panda Resulted In Lower Traffic, But Increased Page Views http://www.webmasterworld.com/google/4444107.htm [webmasterworld.com]
...you mention something else about your traffic...
However, the total number of page views is UP around 3% compared to the month prior, due to the fact that (if google analytics can be trusted*), pages per visit is UP NEARLY 50%
It might be that Google felt your site as a whole deserved to rank, but it wasn't getting a distinct enough signal from your blue-widgets.html page about what kind of visitors liked your site. It could be that Google is now trying to calibrate that.
It may even be that the home page had been getting test traffic to the home page, however Google might have done this, which might have accounted for the increase in page views.
It's also very possible that this shift may not be about your site specifically, but just how Google optimizes its user experience and how they've found,
in situations whose patterns match yours that they can increase visitor stickiness.
I'm guessing, that after this change, Google will further be testing your site (and sites that fit the pattern they see in your site) for user engagement, and will combine patterns they see on many sites... including yours... to further calibrate what they do. It's likely they only test a few factors at a time, so it's a long, slow process.
I would wait for a while for things to settle before making changes, but until then try to figure out how to best use the home page to drive visitors to most appropriate content. It may well be that your content is good, but that your overall design and navigation isn't producing the effect you'd like.
If your product had a long buying cycle, for example, you might want to split up content in such a way that content articles are somewhat distinct from sales pages. At least now (and I take this from a history of your previous posts), you may not be so afraid of breaking up the page and losing your information rankings.
The ongoing tricky aspect of this, though, is how to structure your informational content and your sales pages in parallel so that they help each other. Depending on the site, of course, you try to get links to your informational content and then link to your sales content. Your navigation has to lead to both. By ranking your home page rather than a page that wasn't converting, Google has perhaps liberated you to do this.