aliciagh

Easily search through all blogs into your WordPress MU posts by post title, post content or post author. 
WPMU Global Search can manage multiple search forms. Currently in the following languages:
<ul>
<li>English</li>
<li>Spanish (es_ES)</li>
</ul>
If you have created your own language pack, or have an update of an existing one, you can send <a href="https://codex.wordpress.org/Translating_WordPress" rel="nofollow ugc">gettext .po and .mo files</a> to me so that I can bundle it into WPMU Global Search.

WPMU Global Search

Adds the ability to search through blogs into your WordPress MU installation.

businessbox

Global Content by BusinessBox allows you to define at only one place some content globally used all over your website.
Hence it prevents from writing mutlitple times some hardly-maintenable text.
Plain text as well as more complex HTML/CSS code can be put in each of those global variables.
Simply use this content in either your templates by using our PHP function <code>gcbb_get</code> or directly in the content of posts or pages using a modifiable tag such as <code>[GCBB#variable]</code>.
<h4>Further Reading</h4>
For more info, please visit the links below:
<ul>
<li>Visit our <a href="http://www.businessbox.com.au/" rel="nofollow ugc">website</a></li>
<li>Follow our <a href="http://www.businessbox.com.au/blogs/blog" rel="nofollow ugc">blog</a></li>
<li>Follow BusinessBox on <a href="http://www.linkedin.com/in/philippesoria" rel="nofollow ugc">LinkedIn</a>, <a href="https://twitter.com/businessbox1" rel="nofollow ugc">Twitter</a> & <a href="https://www.facebook.com/pages/Businessbox/438966746178271" rel="nofollow ugc">Facebook</a></li>
</ul>

Global Content by BusinessBox

Define only once some global content and reuse easily in templates and posts/pages as many times as required

WPMU Global Search vs Global Content by BusinessBox