In the old days of the internet, it was quite accepted that on each site/forum/whatever you encountered and wanted to participate in a discussion, you had to make a new account. Nowdays, both due to privacy concerns as well as getting used to be automatically logged in, we have ended up seeing that many people are turned off when they are not able to comment on a site with their Facebook login. For a small blog this means a significant loss in engagement and a chance for more visitors.
I have been looking for a solution for my #WordPress blog, initially trying a Facebook-related plugins (also with integration with Facebook pages), then trying out #Livefyre, which is a complete authentication/comment solution. Livefyre and similar solutions (which I've tried) though will ignore comments that come in from other sources, like the recent Google+ integration I've added. So comments on Google+ were imported in the WordPress database but never shown. Back to the standard WordPress comment module then, but I still needed authentication from social networks.
Installation is as easy as an WordPress #plugin. For Facebook and Twitter integration you will need to create an application on each of them and enter the related API keys in Social Connect's options page. The options page has all the links to guide you through the process.
If everything goes well you will have a the login icons on your comment forms and login page. You will also find a widget for your sidebar available. If there is a problem with your them and the icons don't appear in the comments form, you can call them just with a line of PHP like this
_ <?php do_action( 'social_connect_form' ); ?> _
Users who use the icons will also be added in your WordPress database.
You will find Social Connect at http://wordpress.org/extend/plugins/social-connect/