Jan Štětina

Includes custom HTML/CSS/JS code in the section on every blog in the network.
Very simple, but sometimes useful plugin.
After activation visit Network Admin –> Settings –> Multisite wp_head Code for setup. Nothing else is needed.
Developed for private use, but has perspective for more extensive usage. I can’t guarantee any support in the future nor further development, but it is to be expected. Kindly inform me about bugs, if you find any, or propose new features: <a href="mailto:zaantar@zaantar.eu?subject=[multisite-wphead-code]" rel="nofollow ugc">zaantar@zaantar.eu</a>.

Multisite wp_head Code

Includes custom HTML/CSS/JS code in the  section on every blog in the network.

indowp

This Plugins that makes your site SEO boosting by making your defaut description change everytime you add new post on homepage only. This plugins usefull for those running news site or you are an up to date blogger. 
Many others SEO Plugins doesnt have this feature, they just make keep static description and makes google bored if you have an up to date blog.
<h4>Features</h4>
<ol>
<li>Automatically generate description on your homepage based on last 3 title post, this is real good for your site SEO.</li>
</ol>

Wp SEO Auto Generating Metatag Description

This Plugins that makes your site SEO boosting by making your defaut description change everytime you add new post on homepage only.

Multisite wp_head Code vs Wp SEO Auto Generating Metatag Description