kengher

Broadcast simple, important alerts across your multisite network. Also great for single sites.
Features of Site Alert: 
* Display alert(s) in the Homepage with option to show in all pages of a site. 
* Native WordPress WYSIWYG message creation box for simplicity with media support. 
* Choice of hardcoded at the different parts of the page, or make it a pop-up modal. 
* Indicate different priority levels (colors) and icons. 
* Set a date range to publish/unpublish the alert.
Features as a Network Admin 
* Show alert across all all sites in your multisite network. 
* Exclude alert(s) from certain sites. 
* Site Groups manager to provide easier bulk exclusions.

Super Simple Site Alert

Broadcast simple, important alerts across your multisite network. Also great for single sites.

aleapp

WP Cookies Alert allows to display an alert box on your WordPress blog notifying visitors you blog uses cookies as EU Cookie Law requires. 
You can display a short message or publish a link to a page with extended explenation. 
WP Cookies Alert works in multilingual blogs and can be translated to multiple languages. English and spanish are included.

WP Cookies Alert

This plugin adds an alert box notifying visitors your blog uses cookies.

Super Simple Site Alert vs WP Cookies Alert