Harshit

Automatically subscribes your users so that they can be notified of any new content on the main site using one of the following plugins –
<ul>
<li><a href="https://premium.wpmudev.org/project/subscribe-by-email/" rel="nofollow ugc">WPMU’s Subscribe by Email plugin</a>.</li>
<li><a href="https://wordpress.org/plugins/email-subscribers/" rel="ugc">Email Subscribers & Newsletters</a>.</li>
</ul>
Note
<ul>
<li>In a multisite WordPress install, all the users creating new sites will automatically subscribed to the main site’s new content.</li>
<li>In a single WordPress installation, all users registering to the main site or getting added by other admins will be automatically subscribed to the main site’s new content.</li>
</ul>

Auto Subscribe Users

Helps us automatically subscribe all our new users being added to the multisite network in order send them notifications regarding new updates/important notifications regarding our service.



Works as described

Automatically subscribe your users, so that they can be notified of any new content on the site.

3dperuna

WPMU has great themes and plugins. Unfortunately, many, if not most, come with a nag notice that admins see about installing their notifications dashboard plugin. If you’ve bought one plugin for your site this is probably overkill. If you’re a developer you don’t need this on your client’s sites.
This is a simple plugin that removes the notice. The 1.3 version has been checked against WP 4.4 and recent WPMU plugins, but still should be backwards compatible with older versions of WPMU plugins.
Note: If you do decide to you install the WPMU notifications plugin, please deactivate this one first. Errors may occur if you don’t.
If you like this plugin consider donating: http://www.protospace.com/wpmu-no-nag-plugin/

Remove WPMU Dashboard Install Nag

Works as advertised. Now, why a plugin should be needed for this is another question altogether, and installing and activating this plugin is no substitute for filing an RFE to either add a close button to those annoying nags or a switch to turn them off (and their pref doesn't always work, apparently).
Thanks for this!



Simple and to the point

This plugin removes the nag notice at the top of WPMU plugins and themes.

Auto Subscribe Users vs Remove WPMU Dashboard Install Nag