It has seemed fairly clear since Google launched Google+ that Facebook was worried to at least some extent. That’s not to say Facebook thinks it’s on the cusp of becoming the next Myspace, but when a giant like Google takes your product head on, you have to pay attention, and it’s no doubt a little harder to brush off than if a no-name startup tried the same thing.

Should Facebook be worried about Google+ or vice versa? Let us know your opinion in the comments.

That start-up faces a much larger hill to climb in generating a brand and an audience. Google has a built in audience, and it’s enormous. It has a brand that has been turned into a verb. And that was years ago (though it’s still used very frequently).

So while Facebook may not be in any immediate danger, and Google+ may or may not ever become half the size of Facebook, it’s smart of Facebook to look at what is working with Google+ that some people might like better when comparing to Facebook’s user experience. That’s what Facebook is doing. They did (and continue to do) the same thing with Twitter, and Facebook still reigns supreme in social media.

The latest change is subtle, but noteworthy. They have locked the top navigation bar at the top of the screen, so as you scroll down the page, it is always visible. That means you can always see your notifications and the search box.

Google is also testing locking its navigation. It’s already live on image search, and probably just a matter of time before it’s across Google properties. If you use Google+, this navigation bar contains a link to your Google+ profile and a status update box. That means you’re never too far away from Google+ while you’re using Google.

In Facebook’s case, the sticky navigation bar could increase engagement with the notification counter always visible. Interestingly, it also keeps the search box visible. This could also increase engagement, but if Facebook does more with search, as it has often been speculated that they will (especially now that they’re in such heavy competition with Google), search is always right there. This could potentially make Facebook a greater threat to Google in the search realm. Facebook already taps Bing for its web search results, and Bing is already growing its market share little by little.

Americans alone already (collectively) spend a century on Facebook in a month’s time.

Interestingly, the sticky Facebook navigation bar doesn’t keep the publishers box for posting status updates at the top at all times.

Other things Facebook has done lately that are kind of Google+-esque:

• Circles-like sharing. Last month, Facebook announced new sharing features that make it easier to share things with the people you actually want to share them with. This has been one of the things that people have found most appealing about Google+‘s Circles.
• New friend list options. Just this week, Facebook announced some new options for friends lists, which is really kind of an extension of that last feature. Also like Circles, it’s a way to separate your friends.
• Subscriptions. Also this week, Facebook also announced subscriptions for profiles that share information publicly. Basically, it’s just a way to follow people without them having to follow you back. Twitter has done this for years, but it seem to have taken Google+‘s arrival to get Facebook to offer similar functionality.

There have also been other random signs that Facebook is a little worried about Google+. For example, remember when Facebook blocked that Google+ user’s ad? Facebook has also been stingy about Google+ users getting their FB contacts into Google+.

The point is, in the few short months since Google+ launched, Facebook has rushed to do things that make the two services more alike. To be fair, Google+ (without question) borrowed plenty from Facebook to begin with, but the differences between the two seem to be getting less and less.

That is one major reason why Google+ itself faces a tremendous uphill battle. Facebook is giving users less reasons to like Google+ better. And Facebook already has all of the users. Meanwhile, Google+ gets to keep trying to convince people that it’s the place to be as opposed to Facebook.

Google did finally launch the first Google+ API, which should help in making Google+ more useful as third-party apps are able to build around it.

On the other hand, Google Buzz has APIs too.

It’s not as if Facebook and Google+ can’t co-exist, but Google has put a lot of time and resources in to making Google+ the best Facebook competitor it can be. Will it all be worth it?

Who should be more concerned about its rival’s recent moves: Facebook or Google? Tell us what you think.