Just as the smartphone ate up the PDA’s marketshare, the tablet has quickly stolen a lot of attention from e-readers. In order to continue competing, Amazon and B&N both released their own tablets with locked ecosystems that made them more like glorified e-readers, as opposed to true Android devices.

While Amazon has managed to do reasonably well in creating its own app store, Barnes & Noble’s store was always a bit limited. Today B&N dropped a pretty big bombshell, announcing that Google Play was rolling out to the Nook HD and HD+.

So what’s next for the Nook, and what does this major change mean for the company and for its biggest competitor?

What the move could mean for Amazon

Amazon’s primary advantage over the Nook HD and HD+ was its AppStore, which had several times the amount of apps as the Nook Store. Now the tables have turned. Amazon might have over 50k apps, but Nook HD now has 700k+.

What about hardware, pricing and the UIs? When it comes to hardware and pricing, the Kindle Fire HD 7 and 8.9 are quite comparable to the Nook HD and HD+. The $199 base Kindle Fire HD does have double the storage of the base Nook HD, but Nook makes up for it by including microSD support with its tablets. Another hardware advantage for the Nook is that they have slightly better displays.

That leaves the UI, which is largely a preference thing.

How will this change things for Amazon? It could certainly heat up the competition and give the Kindle Fire line a real challenge. That said, I don’t foresee Amazon biting the bullet and releasing the Play Store to its tablets. Amazon already has a decent amount of content and a pretty loyal following. A little aggressive marketing could be enough to keep Amazon fighting on.

What the move could mean for B&N

B&N might have an edge of Amazon thanks to the Play Store, but they also no longer has full control of the app, book and content situation on their tablets. The big question is whether this change will be profitable for the company or not.

It possible that B&N has already given up and has no plans for a Nook HD successor. Adding Google Play could therefore be a way to push out remaining stock. It’s also possible that B&N is experimenting to see how this new model works for them before they decide on the future of the Nook tablet line.

So what can B&N do to make sure things work out? Marketing, marketing, marketing.

B&N no longer needs to concern themselves with the app portion of their store experience. That means they can work on their core content: books and magazines.

B&N also has the advantage of a store presence. Right now they already have some cool ties to the stores such as free Wi-Fi, the ability to read any B&N e-book while in store for up to an hour, etc. Now it is time for the company to expand on these concepts. B&N is not down and out, if anything this new move could revive interest in the brand.

Should Amazon be worried, or is this just a desperate move by B&N that will make little difference in the long run?