Michal Ozogan

Googles+ widget which provides you public post from your timeline. It shows your statuses, images, videos, links and albums. You need create your google plus app (https://code.google.com/apis/console/b/0/?pli=1) and enter your api + your profile ID. The are also some customizations like size of your profile image, number of showed posts and max width of images.

Easy Google+ Widget

Googles+ widget which provides you public post from your timeline.

Paul Ryan

jojaba

the_elusive

Eduardo Larequi

Anil Natha

pkarjala

Authorizer restricts access to a WordPress site to specific users, typically students enrolled in a university course. It maintains a list of approved users that you can edit to determine who has access. It also replaces the default WordPress login/authorization system with one relying on an external server, such as Google, CAS, LDAP, or an OAuth2 provider. Finally, Authorizer lets you limit invalid login attempts to prevent bots from compromising your users’ accounts.
View or contribute to the plugin source on GitHub: <a href="https://github.com/uhm-coe/authorizer" rel="nofollow ugc">https://github.com/uhm-coe/authorizer</a>
Authorizer requires the following:
<ul>
<li>CAS server (2.x, 3.x, 4.x, 5.x, 6.x, or 7.x) or LDAP server (plugin needs the URL)</li>
<li>PHP extensions: php-ldap, php-curl, php-dom</li>
</ul>
Authorizer provides the following options:
<ul>
<li>Authentication: WordPress accounts; Google accounts; CAS accounts; LDAP accounts; OAuth2 accounts</li>
<li>Login Access: All authenticated users (all local and all external can log in); Only specific users (all local and approved external users can log in)</li>
<li>View Access: Everyone (open access); Only logged in users</li>
<li>Limit Login Attempts: Progressively increase the amount of time required between invalid login attempts.</li>
<li>Shortcode: Use the <code>[authorizer_login_form]</code> shortcode to embed a wp_login_form() outside of wp-login.php.</li>
</ul>

Authorizer

Integrates nicely with Google hosted domain/s. Couldn't be happier with how it works!

Integrates well with Google Logins

I've experimented this plugin on a multisite and everything works pretty well.

Works great even on a multisite setup

Authorizer limits login attempts, restricts access to specific users, and authenticates against external sources (OAuth2, Google, LDAP, or CAS).

Easy Google+ Widget vs Authorizer