rfair404

In the multisite context, creating widgets that are used throughout all of the sites in a network can be difficult and painstaking (at best). 
This plugin gives network administrators the ability to create “fallback widgets” that will be used as the default unless over-ridden by individual sites.
How the plugin works
<ul>
<li>When a widget is created on the “main site” (e.g. site ID 1) the output is cached.</li>
<li>When a sites other than the “main site” (e.g. site ID != 1) call a sidebar that doesn’t have any active widgets, the cached output from the main site will be used.</li>
<li>The plugin may not (read as “probably won’t”) work with highly dynamic widgets</li>
<li>This is the initial release, so please try it out before you use it in a live site.</li>
</ul>

Network Sidebar Widgets

Enables Multisite Networks to create "fallback" widgets that can be used across-network when sites don't have any widgets.

Ipstenu (Mika Epstein)

This plugin adds a new, sortable, column to the users lists, which shows the date and time they registered.
Primarily useful for single site (which doesn’t show this at all), on Multisite Networks it adds the user’s registration info for all individual sites.
<ul>
<li><a href="https://ko-fi.com/A236CEN/" rel="nofollow ugc">Donate</a></li>
<li><a href="http://halfelf.org/plugins/recently-registered/" rel="nofollow ugc">Plugin Site</a></li>
</ul>
<h3>Privacy Notes</h3>
This plugin does not track any additional data other than what WordPress natively collects upon registration. It just makes the data visble.

Recently Registered

Does what it says! It add new column in the user's dashboard!
You can also sort the users by registered date and that is very usefull

Useful. Works great, as I want

Add a sortable column to the users list to show registration date.

Network Sidebar Widgets vs Recently Registered