nivcaner

Message Mate is a simple but wonderful slider add-on to your website that advertises a phone number which current and prospective customers can text with one click to reach you or your employees.
Your customers would rather text than call you. In fact, 76% of young adults prefer to interact with companies via texting (and not through calls, emails, live chat or contact forms). And thankfully for your business, texting is a more efficient and less distracting means of communication.
Texts also have much higher engagement potential with a 97% open rate, at least three times higher than email.
Up to three users can receive and respond to incoming messages via SMS, email, and a web dashboard. And you can even add automated responses and post-conversation rating requests. 
Sell more, with Message Mate. Choose any US area code (subject to availability), and get your first 14 days for free.

Message Mate

Message Mate lets customers text you from their phone or computer. Reply via email, text or dashboard.

ElbowRobo

This plugin is for BuddyPress, it adds a dashboard menu and a tab in the messages section. Once you navigate into the messages section and click the “Mass Messaging” tab you have access to all the options which you chose in the dashboard.
Including mass messaging to:
<ul>
<li>Members</li>
<li>Members of Groups</li>
<li>Members of Blogs (Sites)</li>
</ul>
And:
<ul>
<li>Select all buttons to allow mass messaging to all members easily.</li>
</ul>
In this page you also see ‘subject’ and ‘description’ just like on the Buddypress compose page.

Mass Messaging in BuddyPress

This works great for what I need, thanks a lot!

Great plugin

Ever wanted to send a message to many people at once? Now you can, introducing - Mass Messaging.

Message Mate vs Mass Messaging in BuddyPress