Blogging just got more social: Facebook has launched its Connect Plugin Directory in addition to its Connect program. If you’re a blogger, that means you can let your visitors comment on your site using their Facebook credentials. If you’re a reader, once you comment using your Facebook details, you can have the comment automatically published on your Facebook newsfeed.

Facebook launched almost two weeks ago the Connect program, that lets websites authenticate users with their Facebook login credentials. Now bloggers, thanks to the new Connect Plugin Directory, have a simple way to integrate Connect on their own sites and socialize more with their readers.

Movable Type bloggers got a free plugin that allows any Facebook user to sign in, comment and share their action on a certain site on Facebook. This plugin will also automatically display users’ Facebook photos in one’s comment and can share their comment via the social network’s newsfeed.

In a similar way to Movable Type, WordPress bloggers got a plugin that offers the same commenting possibilities but can also show recent visitors and allow readers to invite friends and share comments. Bloggers that use the Disqus commenting system will also be able to integrate Facebook Connect by the end of the year.

Facebook Connect seems to have a good effect on the number of comments a blog can receive.

Google and MySpace offer similar programs to Facebook’s Connect also. Google’s Friend Connect allows users to sign in with their Google, Yahoo, AIM or OpenID account and interact with other visitors by making friends, sharing media or posting comments. The MySpaceID program works on the same basis and allows users to publish and syndicate their activities to and from partner sites.

One hour after Google did a public launch of Google Friend Connect, Facebook launched Facebook Connect. The simultaneous launch is not a coincidence — the two competing services are battling for mindshare as they strive to be the frontrunners in data portability.

The companies want users to be able to use their Google and Facebook logins to enter third-party sites. It benefits users and third-party sites and allows Facebook and Google to collect more information about what users are doing online.

There are some key differences between the services. Google’s service uses OpenSocial. This means sites using Google Friend Connect can use OpenSocial’s open-source applications, such as message boards and ratings gadgets. Google also lets users sign in with their Yahoo!, AOL and MSN usernames.

However, Facebook has an advantage in terms of partnering with large third-party services. Facebook Connect is already working with Digg, StumbleUpon and Loopt. Google Friend Connect’s partners seem to be smaller sites run by individuals, such as Billboard for the People and Qloud.

It’s too early to say how either service will fare, but the Internet is already buzzing with early feedback from site owners.