Google is currently testing their latest attempt at breaking into social networking: Google Plus. Even though the service is in it’s infancy 3rd party developers are already unleashing extensions to enhance it.

Google has internally dogfooded the application (really it’s several applications loosely tied together) and and are now extensively testing it with a limited number of users. There’s isn’t a public API available to developers yet but that hasn’t slowed down developers who are already busy developing extensions and add-ons to enhance features. Following are four extensions that you can use to enhance Google+.

Google+ Enhancer: Add Unread Item Counts for Gmail, Reader, and Calendar to Google+

Shortly before Google made the announcement about Google+ many people noticed a change the header bar (that displays links of other Google services) across the top of all Google pages. Google+ Enhancer userscript beefs up this bar by adding unread counts to the Google services you use.

Right now it supports Gmail, Reader, and Calendar by giving them the look of Google+’s orange notification button. Apparently you need to be logged in to Google+ to see them. The script requires Greasemonkey to be installed or a browser that supports userscripts to use make it work. This appears to be a very early build as the scripts discussion forum is full of people saying it’s not working on certain browsers. While this didn’t enable unread counts for me while on Google+, it DID enable Google+ to show up on my GMail, GCal, and Reader pages.

Google+ Enhancer

Surplus – Google Plus Integration for Chrome

Surplus brings Google+ notifications right into your Chrome browser. No need to keep Google+ open or rely on emails when things are updated once this is installed. Surplus will allow you to post/respond from within the extension popup window, provides desktop notifications, as well as switch between multiple Google accounts.

Surplus

Extended Share for Google Plus – Share OUTSIDE of Google+

Google+ provides the ability to share an item that someone else posted (provided they let you… one cool feature of G+ is that you can prevent a post from being shared). However, you can only share that post with other Google+ users. Extended Share will add an additional “Sent to…” link to each post on your Google+ page, allowing you to post to Twitter, LinkedIn, and Facebook.

Extended Share for Google Plus

Tweets +1 – Add a +1 button to tweets on twitter.com

With the Tweets + 1 Chrome extension Google’s “+1 button” will appear next to tweets on your twitter timeline. Clicking Google +1 will then display that tweet under ‘+1?s in your Google+ profile. The number of +1?s a tweet has received will also be shown without leaving your Twitter timeline at all.

Note that this extension requires that you have enabled the new interface; it doesn’t work with the old Twitter UI.

Tweets +1

Google Plus Bar Color Changer – Change your Google+ bar color

I personally like the look of the new header bar that Google has rolled out, but to each his own and if you’d prefer something different then the Google Plus Bar Color Changer is for you.

The developer says that it allows you to change the color “because the gray is utterly boring”. By default you only get green out of the Chrome extension gallery… There’s a also a pink and a blue version of the plugin.

Visit his website if you want to know more ways to configure it for additional colors.

Color Plus

Keep in mind that Google+ is still being called an “experiment” by Google and these extensions are just rolling out. Your mileage may vary with both the Google+ service (if you get in) and the extensions as the platform matures.