The #BringBackOurGirls movement picked up momentum before ultimately fading from the international spotlight amidst criticism it was nothing more than "hashtag diplomacy." Indeed, most of the captured girls remain in the Islamic terror group's clutches.

As word of #We_Are_Coming_O_Rome spread across the Italian media, Rome residents took the opportunity to respond to the Islamic State. And they did so in an especially Roman way.  With warnings about the traffic.

The hashtag #AshWednesday trended on Twitter today for the obvious reason: it's Ash Wednesday, the start of Lent, a 40-day period before Easter dedicated to fasting and prayer.  Yet accompanying that trend was another, more interactive hashtag: #ashtag.

Thousands of Saudis have poured into the palace of King Salman who acceded the throne after the death of his half-brother Abdullah last week.  But thousands of others have pledged their allegiance to the new ruler online, taking advantage of social media networks.

The Twitter account for U.S. Central Command was apparently hacked on Monday, with pro-ISIS messages plastering the account's profile.  The first message was posted at 12:29 p.m. ET, with the words "AMERICAN SOLDIERS, WE ARE COMING, WATCH YOUR BACK. ISIS." and the hashtag "#CyberCaliphate."

Following the attack on satirical magazine Charlie Hebdo that left 12 people dead Wednesday in Paris, Twitter users around the world showed their solidarity using the hashtag #JeSuisCharlie, or “I am Charlie.” As of this writing, the hashtag has been used 3.7 million times.